Bootstrap algorithm

We use a simple example to clarify Stata bootstrap algorithm and our coding error. Our simple data set is

use "check_data.dta", clear
xtset ID 
list 
Panel variable: ID (balanced)

     +---------------------------------+
     | ID   year          X          Y |
     |---------------------------------|
  1. |  1   2009    3.96078   10.82663 |
  2. |  1   2010   4.777452   10.68045 |
  3. |  1   2011   5.253614   10.37472 |
  4. |  1   2012   6.620269   10.52382 |
  5. |  1   2013    7.22822   10.88551 |
     |---------------------------------|
  6. |  2   2009   6.293743   20.04308 |
  7. |  2   2010   7.429042   20.04353 |
  8. |  2   2011   8.782087    20.3393 |
  9. |  2   2012   9.068334   20.67591 |
 10. |  2   2013   10.97283    20.2636 |
     |---------------------------------|
 11. |  3   2009   9.125316   30.74265 |
 12. |  3   2010   10.13114   30.82197 |
 13. |  3   2011   11.90619    30.0979 |
 14. |  3   2012   12.72111   30.28484 |
 15. |  3   2013   13.49351   30.46046 |
     +---------------------------------+

To understand how Stata draws observations when we use cluster command, we compare a standard bootstrap with a block (cluster) bootstrap.In this exercise, we regress Y on X and get standard errors from a bootstrap. The following code is to run a standard bootstrap for 50 repetitions.

bootstrap, reps(50) seed(123) saving("check_c",replace): reg Y X
(running regress on estimation sample)

Bootstrap replications (50): .........10.........20.........30.........40.........50 
> done

Linear regression                                       Number of obs =     15
                                                        Replications  =     50
                                                        Wald chi2(1)  =  54.32
                                                        Prob > chi2   = 0.0000
                                                        R-squared     = 0.7232
                                                        Adj R-squared = 0.7019
                                                        Root MSE      = 4.5760

------------------------------------------------------------------------------
             |   Observed   Bootstrap                         Normal-based
           Y | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------+----------------------------------------------------------------
           X |   2.433785   .3302071     7.37   0.000     1.786591    3.080979
       _cons |  -.2589922   2.942226    -0.09   0.930     -6.02565    5.507665
------------------------------------------------------------------------------

OLS estimates in each repetition are stored in the “check_c” file.

use "check_c.dta", clear
list
(bootstrap: regress)

     +----------------------+
     |     _b_X     _b_cons |
     |----------------------|
  1. | 2.138077    .5576385 |
  2. | 2.417894   -.7642964 |
  3. | 1.693039    6.641975 |
  4. |  3.05896    -4.37361 |
  5. | 2.187195    .6708606 |
     |----------------------|
  6. | 2.430729    .8148106 |
  7. | 2.593253   -1.905666 |
  8. | 2.674258   -.1598216 |
  9. | 2.188795    1.348569 |
 10. | 2.020593    1.501604 |
     |----------------------|
 11. | 2.432382   -.7704033 |
 12. | 2.584248   -.7272254 |
 13. | 1.747556    6.859074 |
 14. | 2.238197    3.712923 |
 15. | 2.437271   -2.209589 |
     |----------------------|
 16. | 1.648717     6.51654 |
 17. | 2.717264    -2.56621 |
 18. |  2.02047    5.002777 |
 19. | 2.460462   -.4938909 |
 20. | 2.527794   -1.437341 |
     |----------------------|
 21. | 2.328885     .048876 |
 22. | 2.326322    2.270131 |
 23. | 2.488114    1.471417 |
 24. | 2.291409     2.62575 |
 25. |  2.33052    1.138789 |
     |----------------------|
 26. | 3.205872   -5.360022 |
 27. | 2.152287     2.59953 |
 28. | 2.213326    .0051833 |
 29. | 3.301715   -9.769567 |
 30. | 2.661102    .0862941 |
     |----------------------|
 31. | 2.170336    2.193878 |
 32. | 2.166642    1.234382 |
 33. | 2.619741   -.7812752 |
 34. | 2.111542    .9451756 |
 35. |  2.25625    .9069682 |
     |----------------------|
 36. | 2.189938    2.277627 |
 37. | 2.554644   -1.451359 |
 38. | 2.226695    1.243645 |
 39. | 2.168588    .7011353 |
 40. | 2.699125   -1.588767 |
     |----------------------|
 41. | 2.320445   -.2368655 |
 42. | 2.422203    .3315688 |
 43. | 2.663802   -1.305801 |
 44. | 2.309478    2.289144 |
 45. |  2.41109   -.4334617 |
     |----------------------|
 46. | 2.341678    1.177642 |
 47. |  2.48314    -.049209 |
 48. | 2.849747   -5.127273 |
 49. | 2.412701   -1.892364 |
 50. | 1.905824    2.818149 |
     +----------------------+

The standard deviation of these estimates of X (_b_X variable) should correspond to the bootstrap standard error above.

su _b_X,d
scalar std_c = r(sd)
                            _b[X]
-------------------------------------------------------------
      Percentiles      Smallest
 1%     1.648717       1.648717
 5%     1.747556       1.693039
10%     2.020531       1.747556       Obs                  50
25%     2.187195       1.905824       Sum of wgt.          50

50%     2.336099                      Mean           2.376006
                        Largest       Std. dev.      .3302071
75%     2.554644       2.849747
90%     2.708195        3.05896       Variance       .1090367
95%      3.05896       3.205872       Skewness       .4210463
99%     3.301715       3.301715       Kurtosis       4.007335
scalar list std_c
     std_c =  .33020705

We move to a block (cluster) bootstrap. The key objective of this exercise is to make sure that in the block bootstrap Stata draws all observations for a given firm when it picks up a firm at random by block bootstrap. (We were initially not quite sure if that was the case or whether perhaps Stata would pick just some, not all observations from each firm (block) it selected for bootstrap.) Load our simple data set.

use "check_data.dta", clear
xtset ID 
list 
Panel variable: ID (balanced)

     +---------------------------------+
     | ID   year          X          Y |
     |---------------------------------|
  1. |  1   2009    3.96078   10.82663 |
  2. |  1   2010   4.777452   10.68045 |
  3. |  1   2011   5.253614   10.37472 |
  4. |  1   2012   6.620269   10.52382 |
  5. |  1   2013    7.22822   10.88551 |
     |---------------------------------|
  6. |  2   2009   6.293743   20.04308 |
  7. |  2   2010   7.429042   20.04353 |
  8. |  2   2011   8.782087    20.3393 |
  9. |  2   2012   9.068334   20.67591 |
 10. |  2   2013   10.97283    20.2636 |
     |---------------------------------|
 11. |  3   2009   9.125316   30.74265 |
 12. |  3   2010   10.13114   30.82197 |
 13. |  3   2011   11.90619    30.0979 |
 14. |  3   2012   12.72111   30.28484 |
 15. |  3   2013   13.49351   30.46046 |
     +---------------------------------+

The following code is to run a block bootstrap for 50 repetitions.

bootstrap, reps(50) seed(123) cluster(ID) idcluster(Newid) saving("check_p", replace): reg Y X
> e): reg Y X
(running regress on estimation sample)

Bootstrap replications (50): .........10.........20.........30.........40.........50 
> done

Linear regression                                       Number of obs =     15
                                                        Replications  =     50
                                                        Wald chi2(1)  =   7.16
                                                        Prob > chi2   = 0.0075
                                                        R-squared     = 0.7232
                                                        Adj R-squared = 0.7019
                                                        Root MSE      = 4.5760

                                      (Replications based on 3 clusters in ID)
------------------------------------------------------------------------------
             |   Observed   Bootstrap                         Normal-based
           Y | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------+----------------------------------------------------------------
           X |   2.433785   .9097357     2.68   0.007     .6507359    4.216834
       _cons |  -.2589922   8.415041    -0.03   0.975    -16.75217    16.23419
------------------------------------------------------------------------------

We can check the distribution of OLS estimates stored in the “check_p” file. The standard deviation of these estimates of X (_b_X variable) should be the same as the bootstrap standard error above.

use "check_p.dta", clear
su _b_X,d
scalar std_p  = r(sd)
(bootstrap: regress)

                            _b[X]
-------------------------------------------------------------
      Percentiles      Smallest
 1%    -.1159865      -.1159865
 5%     .0051345      -.1159865
10%      .041567       .0051345       Obs                  50
25%     1.450909       .0051345       Sum of wgt.          50

50%     1.576175                      Mean           1.655174
                        Largest       Std. dev.      .9097357
75%     2.433785       2.704328
90%     2.586121       2.704328       Variance        .827619
95%     2.704328       2.704328       Skewness      -.7171314
99%     2.704328       2.704328       Kurtosis       2.423586
scalar list std_p
     std_p =  .90973567

To investigate where these estimates come from, we cross-tabulate these estimates of X and a constant.

tab _b_X _b_cons
           |                       _b[_cons]
     _b[X] | -3.117049  -.7107261  -.2589922   2.658958   5.201381 |     Total
-----------+-------------------------------------------------------+----------
 -.1159865 |         0          0          0          0          0 |         2 
  .0051345 |         0          0          0          0          0 |         3 
  .0779996 |         0          0          0          0          0 |         4 
  1.450909 |         0          0          0          0          0 |         8 
  1.501025 |         0          0          0          0          0 |         5 
  1.576175 |         0          0          0          0          6 |         6 
  1.710974 |         0          0          0          2          0 |         2 
  2.433785 |         0          0         10          0          0 |        10 
  2.586121 |         0          6          0          0          0 |         6 
  2.704328 |         4          0          0          0          0 |         4 
-----------+-------------------------------------------------------+----------
     Total |         4          6         10          2          6 |        50 

           |                       _b[_cons]
     _b[X] |  9.419242   10.62963   11.86349   19.60937   31.81256 |     Total
-----------+-------------------------------------------------------+----------
 -.1159865 |         0          0          0          0          2 |         2 
  .0051345 |         0          3          0          0          0 |         3 
  .0779996 |         0          0          0          4          0 |         4 
  1.450909 |         0          0          8          0          0 |         8 
  1.501025 |         5          0          0          0          0 |         5 
  1.576175 |         0          0          0          0          0 |         6 
  1.710974 |         0          0          0          0          0 |         2 
  2.433785 |         0          0          0          0          0 |        10 
  2.586121 |         0          0          0          0          0 |         6 
  2.704328 |         0          0          0          0          0 |         4 
-----------+-------------------------------------------------------+----------
     Total |         5          3          8          4          2 |        50 

As we can see above, these estimates come from 10 possible combinations of blocks (IDs). For instance, suppose that Stata picks ID=1, ID=1, and ID=2. In this case, our data are

use "check_data_ID_1.dta", clear
append using "check_data_ID_1.dta"
append using "check_data_ID_2.dta"
list
     | ID   year          X          Y |
     |---------------------------------|
  1. |  1   2009    3.96078   10.82663 |
  2. |  1   2010   4.777452   10.68045 |
  3. |  1   2011   5.253614   10.37472 |
  4. |  1   2012   6.620269   10.52382 |
  5. |  1   2013    7.22822   10.88551 |
     |---------------------------------|
  6. |  1   2009    3.96078   10.82663 |
  7. |  1   2010   4.777452   10.68045 |
  8. |  1   2011   5.253614   10.37472 |
  9. |  1   2012   6.620269   10.52382 |
 10. |  1   2013    7.22822   10.88551 |
     |---------------------------------|
 11. |  2   2009   6.293743   20.04308 |
 12. |  2   2010   7.429042   20.04353 |
 13. |  2   2011   8.782087    20.3393 |
 14. |  2   2012   9.068334   20.67591 |
 15. |  2   2013   10.97283    20.2636 |
     +---------------------------------+

We use this data set to regress Y on X.

reg Y X
estimates store m1
      Source |       SS           df       MS      Number of obs   =        15
-------------+----------------------------------   F(1, 13)        =     14.55
       Model |  163.078415         1  163.078415   Prob > F        =    0.0021
    Residual |  145.703509        13  11.2079622   R-squared       =    0.5281
-------------+----------------------------------   Adj R-squared   =    0.4918
       Total |  308.781924        14  22.0558517   Root MSE        =    3.3478

------------------------------------------------------------------------------
           Y | Coefficient  Std. err.      t    P>|t|     [95% conf. interval]
-------------+----------------------------------------------------------------
           X |   1.710973   .4485474     3.81   0.002     .7419457    2.680001
       _cons |   2.658958    3.06184     0.87   0.401    -3.955745    9.273661
------------------------------------------------------------------------------

The estimates (1.710973, 2.658958) are in the cross-tabulation above. This means that Stata chooses IDs randomly and draws all the observations of a firm. We can check other estimates in a similar way.

use "check_data_ID_1.dta", clear
append using "check_data_ID_1.dta"
append using "check_data_ID_1.dta"
quietly: reg Y X
estimates store m2
use "check_data_ID_1.dta", clear
append using "check_data_ID_1.dta"
append using "check_data_ID_3.dta"
quietly: reg Y X
estimates store m3
use "check_data_ID_1.dta", clear
append using "check_data_ID_2.dta"
append using "check_data_ID_2.dta"
quietly: reg Y X
estimates store m4
use "check_data_ID_1.dta", clear
append using "check_data_ID_3.dta"
append using "check_data_ID_3.dta"
quietly: reg Y X
estimates store m5
use "check_data_ID_2.dta", clear
append using "check_data_ID_2.dta"
append using "check_data_ID_3.dta"
quietly: reg Y X
estimates store m6
use "check_data_ID_2.dta", clear
append using "check_data_ID_3.dta"
append using "check_data_ID_3.dta"
quietly: reg Y X
estimates store m7
use "check_data_ID_2.dta", clear
append using "check_data_ID_2.dta"
append using "check_data_ID_2.dta"
quietly: reg Y X
estimates store m8
use "check_data_ID_3.dta", clear
append using "check_data_ID_3.dta"
append using "check_data_ID_3.dta"
quietly: reg Y X
estimates store m9
use "check_data_ID_1.dta", clear
append using "check_data_ID_2.dta"
append using "check_data_ID_3.dta"
quietly: reg Y X
estimates store m10

The estimates from these OLS regressions are

estimates tab m1 m2 m3 m4 m5 m6 m7 m8 m9 m10
    Variable |     m1           m2           m3           m4           m5      
-------------+-----------------------------------------------------------------
           X |  1.7109734    .00513446    2.7043283     1.576175    2.5861213  
       _cons |  2.6589585    10.629635   -3.1170485    5.2013813   -.71072607  
-------------------------------------------------------------------------------


-------------------------------------------------------------------------------
    Variable |     m6           m7           m8           m9          m10      
-------------+-----------------------------------------------------------------
           X |  1.5010249    1.4509086    .07799959   -.11598655    2.4337851  
       _cons |  9.4192416    11.863486    19.609368    31.812562   -.25899216  
-------------------------------------------------------------------------------

The estimates on X from the block bootstrap are displayed again.

use "check_p.dta", clear
tab _b_X
(bootstrap: regress)

      _b[X] |      Freq.     Percent        Cum.
------------+-----------------------------------
  -.1159865 |          2        4.00        4.00
   .0051345 |          3        6.00       10.00
   .0779996 |          4        8.00       18.00
   1.450909 |          8       16.00       34.00
   1.501025 |          5       10.00       44.00
   1.576175 |          6       12.00       56.00
   1.710974 |          2        4.00       60.00
   2.433785 |         10       20.00       80.00
   2.586121 |          6       12.00       92.00
   2.704328 |          4        8.00      100.00
------------+-----------------------------------
      Total |         50      100.00

We have now confirmed that all the observations of a firm are drawn when that firm is randomly chosen by block bootstrap.

Our coding mistake

We continue to use our simple data.

use "check_data.dta", clear
xtset ID 
list 
Panel variable: ID (balanced)

     +---------------------------------+
     | ID   year          X          Y |
     |---------------------------------|
  1. |  1   2009    3.96078   10.82663 |
  2. |  1   2010   4.777452   10.68045 |
  3. |  1   2011   5.253614   10.37472 |
  4. |  1   2012   6.620269   10.52382 |
  5. |  1   2013    7.22822   10.88551 |
     |---------------------------------|
  6. |  2   2009   6.293743   20.04308 |
  7. |  2   2010   7.429042   20.04353 |
  8. |  2   2011   8.782087    20.3393 |
  9. |  2   2012   9.068334   20.67591 |
 10. |  2   2013   10.97283    20.2636 |
     |---------------------------------|
 11. |  3   2009   9.125316   30.74265 |
 12. |  3   2010   10.13114   30.82197 |
 13. |  3   2011   11.90619    30.0979 |
 14. |  3   2012   12.72111   30.28484 |
 15. |  3   2013   13.49351   30.46046 |
     +---------------------------------+

First, we use Stata ado file, bootstrap_check_1, that mimics our AER boos_2sls_1. We basically generate X_cum from X for each ID, and then regress Y on X_cum. he mistake in our ado file was that we used ID.

program bootstrap_check_1,rclass
version 16
tempname b V 

capture drop X_cum

sort ID year
by ID: gen X_cum = sum(X)
reg Y X_cum
matrix `b' = e(b)
matrix `V' = e(V)
ereturn post `b' `V' 
 
end

We do a block bootstrap by Stata.

generate newid = ID
tsset newid year
sysdir set PERSONAL "/Applications/Stata/ado/personal/"
bootstrap _b _se, rep(50)   seed(123) cluster(ID) idcluster(newid) saving("check_code_1", replace) nowarn: bootstrap_check_1
Panel variable: newid (strongly balanced)
 Time variable: year, 2009 to 2013
         Delta: 1 unit


(running bootstrap_check_1 on estimation sample)

Bootstrap replications (50): .........10.........20.........30.........40.........50 
> done

Bootstrap results                                           Number of obs = 15
                                                            Replications  = 50

                                      (Replications based on 3 clusters in ID)
------------------------------------------------------------------------------
             |   Observed   Bootstrap                         Normal-based
             | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------+----------------------------------------------------------------
b            |
       X_cum |   .2500074   .0980365     2.55   0.011     .0578593    .4421555
       _cons |   14.59429   5.177171     2.82   0.005     4.447224    24.74136
-------------+----------------------------------------------------------------
se           |
       X_cum |   .1324635    .050064     2.65   0.008     .0343398    .2305872
       _cons |   3.695125   1.446516     2.55   0.011     .8600048    6.530245
------------------------------------------------------------------------------

The OLS estimates generated by the bootstrap are stored in the “check_code_1” file. To investigate where these estimates come from, we cross-tabulate these estimates.

use "check_code_1", clear
tab _b_X _b_cons
(bootstrap: bootstrap_check_1)

           |                       _b[_cons]
 _b[X_cum] |  10.64108   13.76844   14.59429   14.69029   15.17088 |     Total
-----------+-------------------------------------------------------+----------
 -.0397966 |         0          0          0          0          0 |         5 
 -.0318632 |         0          0          0          2          0 |         2 
 -.0028765 |         0          0          0          0          0 |         2 
  .0004337 |         3          0          0          0          0 |         3 
  .0037811 |         0          0          0          0          0 |         4 
   .070108 |         0          0          0          0          0 |         8 
  .0724891 |         0          0          0          0          4 |         4 
  .0991575 |         0          6          0          0          0 |         6 
  .1549924 |         0          0          0          0          0 |         6 
  .2500074 |         0          0         10          0          0 |        10 
-----------+-------------------------------------------------------+----------
     Total |         3          6         10          2          4 |        50 

           |                       _b[_cons]
 _b[X_cum] |  17.04391   20.04064   23.79541   25.22751   30.72609 |     Total
-----------+-------------------------------------------------------+----------
 -.0397966 |         0          0          0          5          0 |         5 
 -.0318632 |         0          0          0          0          0 |         2 
 -.0028765 |         0          0          0          0          2 |         2 
  .0004337 |         0          0          0          0          0 |         3 
  .0037811 |         0          4          0          0          0 |         4 
   .070108 |         0          0          8          0          0 |         8 
  .0724891 |         0          0          0          0          0 |         4 
  .0991575 |         0          0          0          0          0 |         6 
  .1549924 |         6          0          0          0          0 |         6 
  .2500074 |         0          0          0          0          0 |        10 
-----------+-------------------------------------------------------+----------
     Total |         6          4          8          5          2 |        50 

To see our mistake, suppose that Stata picks ID=1, ID=1, and ID=2. In this case, our data are

use "check_data_ID_1.dta", clear
append using "check_data_ID_1.dta"
append using "check_data_ID_2.dta"
list
     | ID   year          X          Y |
     |---------------------------------|
  1. |  1   2009    3.96078   10.82663 |
  2. |  1   2010   4.777452   10.68045 |
  3. |  1   2011   5.253614   10.37472 |
  4. |  1   2012   6.620269   10.52382 |
  5. |  1   2013    7.22822   10.88551 |
     |---------------------------------|
  6. |  1   2009    3.96078   10.82663 |
  7. |  1   2010   4.777452   10.68045 |
  8. |  1   2011   5.253614   10.37472 |
  9. |  1   2012   6.620269   10.52382 |
 10. |  1   2013    7.22822   10.88551 |
     |---------------------------------|
 11. |  2   2009   6.293743   20.04308 |
 12. |  2   2010   7.429042   20.04353 |
 13. |  2   2011   8.782087    20.3393 |
 14. |  2   2012   9.068334   20.67591 |
 15. |  2   2013   10.97283    20.2636 |
     +---------------------------------+

We apply the bootstrap_check_1 ado file to this data set. We first calculate a cumulative sum of X.

sort ID year
by ID: gen X_cum = sum(X)
list
     | ID   year          X          Y      X_cum |
     |--------------------------------------------|
  1. |  1   2009    3.96078   10.82663    3.96078 |
  2. |  1   2009    3.96078   10.82663   7.921559 |
  3. |  1   2010   4.777452   10.68045   12.69901 |
  4. |  1   2010   4.777452   10.68045   17.47646 |
  5. |  1   2011   5.253614   10.37472   22.73008 |
     |--------------------------------------------|
  6. |  1   2011   5.253614   10.37472   27.98369 |
  7. |  1   2012   6.620269   10.52382   34.60396 |
  8. |  1   2012   6.620269   10.52382   41.22423 |
  9. |  1   2013    7.22822   10.88551   48.45245 |
 10. |  1   2013    7.22822   10.88551   55.68067 |
     |--------------------------------------------|
 11. |  2   2009   6.293743   20.04308   6.293743 |
 12. |  2   2010   7.429042   20.04353   13.72278 |
 13. |  2   2011   8.782087    20.3393   22.50487 |
 14. |  2   2012   9.068334   20.67591   31.57321 |
 15. |  2   2013   10.97283    20.2636   42.54604 |
     +--------------------------------------------+

There are two ID=1 firms, but they are treated as the same firm. Using ID to sort observations ends up with calculating a cumulative sum of X wrongly for ID=1 firm. When we use this data set and run regression, we obtain

reg Y X_cum 
      Source |       SS           df       MS      Number of obs   =        15
-------------+----------------------------------   F(1, 13)        =      0.16
       Model |  3.67901674         1  3.67901674   Prob > F        =    0.6986
    Residual |  305.102907        13  23.4694544   R-squared       =    0.0119
-------------+----------------------------------   Adj R-squared   =   -0.0641
       Total |  308.781924        14  22.0558517   Root MSE        =    4.8445

------------------------------------------------------------------------------
           Y | Coefficient  Std. err.      t    P>|t|     [95% conf. interval]
-------------+----------------------------------------------------------------
       X_cum |  -.0318632   .0804777    -0.40   0.699    -.2057247    .1419982
       _cons |   14.69029   2.434912     6.03   0.000     9.429983     19.9506
------------------------------------------------------------------------------

To display OLS estimates in the bootstrap,

use "check_code_1", clear
tab _b_X _b_cons
(bootstrap: bootstrap_check_1)

           |                       _b[_cons]
 _b[X_cum] |  10.64108   13.76844   14.59429   14.69029   15.17088 |     Total
-----------+-------------------------------------------------------+----------
 -.0397966 |         0          0          0          0          0 |         5 
 -.0318632 |         0          0          0          2          0 |         2 
 -.0028765 |         0          0          0          0          0 |         2 
  .0004337 |         3          0          0          0          0 |         3 
  .0037811 |         0          0          0          0          0 |         4 
   .070108 |         0          0          0          0          0 |         8 
  .0724891 |         0          0          0          0          4 |         4 
  .0991575 |         0          6          0          0          0 |         6 
  .1549924 |         0          0          0          0          0 |         6 
  .2500074 |         0          0         10          0          0 |        10 
-----------+-------------------------------------------------------+----------
     Total |         3          6         10          2          4 |        50 

           |                       _b[_cons]
 _b[X_cum] |  17.04391   20.04064   23.79541   25.22751   30.72609 |     Total
-----------+-------------------------------------------------------+----------
 -.0397966 |         0          0          0          5          0 |         5 
 -.0318632 |         0          0          0          0          0 |         2 
 -.0028765 |         0          0          0          0          2 |         2 
  .0004337 |         0          0          0          0          0 |         3 
  .0037811 |         0          4          0          0          0 |         4 
   .070108 |         0          0          8          0          0 |         8 
  .0724891 |         0          0          0          0          0 |         4 
  .0991575 |         0          0          0          0          0 |         6 
  .1549924 |         6          0          0          0          0 |         6 
  .2500074 |         0          0          0          0          0 |        10 
-----------+-------------------------------------------------------+----------
     Total |         6          4          8          5          2 |        50 

We can see (-.0318632, 14.69029) in the cross-tabulation table. The OLS estimation above is what the bootstrap using the bootstrap_check_1 ado file does. This was our error.

We now switch to use a modified ado file, bootstrap_check_2.

program bootstrap_check_2,rclass
version 16
tempname b V 

capture drop X_cum

sort newid year
by newid: gen X_cum = sum(X)
reg Y X_cum
matrix `b' = e(b)
matrix `V' = e(V)
ereturn post `b' `V' 
 
end

We replace ID with newid in this modified ado file, and we use this ado file to do a block bootstrap.

use "check_data.dta", clear
generate newid = ID
tsset newid year
sysdir set PERSONAL "/Applications/Stata/ado/personal/"
bootstrap _b _se, rep(50)   seed(123) cluster(ID) idcluster(newid) saving("check_code_2", replace) nowarn: bootstrap_check_2
Panel variable: newid (strongly balanced)
 Time variable: year, 2009 to 2013
         Delta: 1 unit


(running bootstrap_check_2 on estimation sample)

Bootstrap replications (50): .........10.........20.........30.........40.........50 
> done

Bootstrap results                                           Number of obs = 15
                                                            Replications  = 50

                                      (Replications based on 3 clusters in ID)
------------------------------------------------------------------------------
             |   Observed   Bootstrap                         Normal-based
             | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------+----------------------------------------------------------------
b            |
       X_cum |   .2500074    .110787     2.26   0.024     .0328689    .4671459
       _cons |   14.59429   5.524413     2.64   0.008     3.766643    25.42194
-------------+----------------------------------------------------------------
se           |
       X_cum |   .1324635   .0477348     2.77   0.006     .0389049    .2260221
       _cons |   3.695125   1.358591     2.72   0.007     1.032335    6.357914
------------------------------------------------------------------------------

OLS estimates in the bootstrap are

use "check_code_2", clear
tab _b_X _b_cons
(bootstrap: bootstrap_check_2)

           |                       _b[_cons]
 _b[X_cum] |  9.930254   10.63928   11.08247   14.44029   14.59429 |     Total
-----------+-------------------------------------------------------+----------
 -.0087411 |         0          0          0          0          0 |         2 
  .0012603 |         0          3          0          0          0 |         3 
  .0112229 |         0          0          0          0          0 |         4 
  .0706006 |         0          0          0          0          0 |         8 
  .0907742 |         0          0          0          0          0 |         5 
  .1278033 |         0          0          0          6          0 |         6 
   .156262 |         0          0          2          0          0 |         2 
  .2500074 |         0          0          0          0         10 |        10 
   .258613 |         0          0          0          0          0 |         6 
  .3537096 |         4          0          0          0          0 |         4 
-----------+-------------------------------------------------------+----------
     Total |         4          3          2          6         10 |        50 

           |                       _b[_cons]
 _b[X_cum] |   17.0334   20.01127   21.29105   25.01602   30.76269 |     Total
-----------+-------------------------------------------------------+----------
 -.0087411 |         0          0          0          0          2 |         2 
  .0012603 |         0          0          0          0          0 |         3 
  .0112229 |         0          4          0          0          0 |         4 
  .0706006 |         0          0          0          8          0 |         8 
  .0907742 |         0          0          5          0          0 |         5 
  .1278033 |         0          0          0          0          0 |         6 
   .156262 |         0          0          0          0          0 |         2 
  .2500074 |         0          0          0          0          0 |        10 
   .258613 |         6          0          0          0          0 |         6 
  .3537096 |         0          0          0          0          0 |         4 
-----------+-------------------------------------------------------+----------
     Total |         6          4          5          8          2 |        50 

We now have a different distribution of OLS estimates. To see how this ado file works, suppose that Stata picks ID=1, ID=1, and ID=2. To treat two ID=1 firms differently, we create newid and change ID of the first one to newid=4. In this case, our data are

use "check_data_ID_1.dta", clear
gen newid=4
append using "check_data_ID_1.dta"
replace newid=1 if newid==.
append using "check_data_ID_2.dta"
replace newid=2 if newid==.
list
(5 real changes made)


(5 real changes made)

     +-----------------------------------------+
     | ID   year          X          Y   newid |
     |-----------------------------------------|
  1. |  1   2009    3.96078   10.82663       4 |
  2. |  1   2010   4.777452   10.68045       4 |
  3. |  1   2011   5.253614   10.37472       4 |
  4. |  1   2012   6.620269   10.52382       4 |
  5. |  1   2013    7.22822   10.88551       4 |
     |-----------------------------------------|
  6. |  1   2009    3.96078   10.82663       1 |
  7. |  1   2010   4.777452   10.68045       1 |
  8. |  1   2011   5.253614   10.37472       1 |
  9. |  1   2012   6.620269   10.52382       1 |
 10. |  1   2013    7.22822   10.88551       1 |
     |-----------------------------------------|
 11. |  2   2009   6.293743   20.04308       2 |
 12. |  2   2010   7.429042   20.04353       2 |
 13. |  2   2011   8.782087    20.3393       2 |
 14. |  2   2012   9.068334   20.67591       2 |
 15. |  2   2013   10.97283    20.2636       2 |
     +-----------------------------------------+

We apply the bootstrap_check_2 ado file to this data set. We first calculate a cumulative sum of X.

sort newid year
by newid: gen X_cum = sum(X)
list
     | ID   year          X          Y   newid      X_cum |
     |----------------------------------------------------|
  1. |  1   2009    3.96078   10.82663       1    3.96078 |
  2. |  1   2010   4.777452   10.68045       1   8.738232 |
  3. |  1   2011   5.253614   10.37472       1   13.99185 |
  4. |  1   2012   6.620269   10.52382       1   20.61211 |
  5. |  1   2013    7.22822   10.88551       1   27.84033 |
     |----------------------------------------------------|
  6. |  2   2009   6.293743   20.04308       2   6.293743 |
  7. |  2   2010   7.429042   20.04353       2   13.72278 |
  8. |  2   2011   8.782087    20.3393       2   22.50487 |
  9. |  2   2012   9.068334   20.67591       2   31.57321 |
 10. |  2   2013   10.97283    20.2636       2   42.54604 |
     |----------------------------------------------------|
 11. |  1   2009    3.96078   10.82663       4    3.96078 |
 12. |  1   2010   4.777452   10.68045       4   8.738232 |
 13. |  1   2011   5.253614   10.37472       4   13.99185 |
 14. |  1   2012   6.620269   10.52382       4   20.61211 |
 15. |  1   2013    7.22822   10.88551       4   27.84033 |
     +----------------------------------------------------+

There are once again two ID=1 firms. However, they are treated as different firms because of newid. Using newid to sort observations leads to calculating a cumulative sum of X correctly. When we use this data set and run regression, we obtain

reg Y X_cum 
      Source |       SS           df       MS      Number of obs   =        15
-------------+----------------------------------   F(1, 13)        =      2.11
       Model |  43.1447212         1  43.1447212   Prob > F        =    0.1699
    Residual |  265.637203        13   20.433631   R-squared       =    0.1397
-------------+----------------------------------   Adj R-squared   =    0.0736
       Total |  308.781924        14  22.0558517   Root MSE        =    4.5204

------------------------------------------------------------------------------
           Y | Coefficient  Std. err.      t    P>|t|     [95% conf. interval]
-------------+----------------------------------------------------------------
       X_cum |    .156262   .1075381     1.45   0.170    -.0760599    .3885839
       _cons |   11.08247     2.2415     4.94   0.000     6.240005    15.92494
------------------------------------------------------------------------------

To display OLS estimates in the bootstrap,

use "check_code_2", clear
tab _b_X _b_cons
(bootstrap: bootstrap_check_2)

           |                       _b[_cons]
 _b[X_cum] |  9.930254   10.63928   11.08247   14.44029   14.59429 |     Total
-----------+-------------------------------------------------------+----------
 -.0087411 |         0          0          0          0          0 |         2 
  .0012603 |         0          3          0          0          0 |         3 
  .0112229 |         0          0          0          0          0 |         4 
  .0706006 |         0          0          0          0          0 |         8 
  .0907742 |         0          0          0          0          0 |         5 
  .1278033 |         0          0          0          6          0 |         6 
   .156262 |         0          0          2          0          0 |         2 
  .2500074 |         0          0          0          0         10 |        10 
   .258613 |         0          0          0          0          0 |         6 
  .3537096 |         4          0          0          0          0 |         4 
-----------+-------------------------------------------------------+----------
     Total |         4          3          2          6         10 |        50 

           |                       _b[_cons]
 _b[X_cum] |   17.0334   20.01127   21.29105   25.01602   30.76269 |     Total
-----------+-------------------------------------------------------+----------
 -.0087411 |         0          0          0          0          2 |         2 
  .0012603 |         0          0          0          0          0 |         3 
  .0112229 |         0          4          0          0          0 |         4 
  .0706006 |         0          0          0          8          0 |         8 
  .0907742 |         0          0          5          0          0 |         5 
  .1278033 |         0          0          0          0          0 |         6 
   .156262 |         0          0          0          0          0 |         2 
  .2500074 |         0          0          0          0          0 |        10 
   .258613 |         6          0          0          0          0 |         6 
  .3537096 |         0          0          0          0          0 |         4 
-----------+-------------------------------------------------------+----------
     Total |         6          4          5          8          2 |        50 

We can see (.156262, 11.08247) in the cross-tabulation table. The OLS estimation above is what the bootstrap using the bootstrap_check_2 ado file does. This was indeed our intended estimation.

Replicating and correcting estimates in columns (3) and (4) in Table 5 of the AER paper

The original estimation results

The results of (3) in Table 5

We first reproduce the estimation results published in the AER by using our data.

use "/Users/atsushiohyama/Desktop/bootstrap_checks/main_data_check.dta", clear

The ado file we use is as follows.

program boos_2sls_1_original, eclass
version 16
tempname b V
*tempvar num_exper_upgrades_st_hat 
*tempvar num_exper_upgrades_st_cum_hat

capture drop num_exper_upgrades_st_hat num_exper_upgrades_st_cum_hat

poisson num_exper_upgrades_st  c.sotan_c#c.dlog_high_end_cap fr_low_prod u_eng_dummy  merchant_d ///
dlog_high_end_cap dlog_low_end_cap log_firm_total firm_age i.year_half_year  if est_inc==1 , robust cluster(firmID)


 
predict num_exper_upgrades_st_hat if e(sample)
sort firmID year_half_year
by firmID: gen num_exper_upgrades_st_cum_hat=sum(num_exper_upgrades_st_hat)

reg dlog_firm_total num_exper_upgrades_st_cum_hat  fr_low_prod   u_eng_dummy  merchant_d  ///
dlog_high_end_cap dlog_low_end_cap   log_firm_total  firm_age i.year_half_year  if  est_inc==1


matrix `b' = e(b)
matrix `V' = e(V)
ereturn post `b' `V' 
end
d

The following codes are to do a block bootstrap.

xtset, clear
quietly: xtset firmID
gen  newid = firmID
quietly: tsset newid year_half_year
quietly: keep if est_inc
sysdir set PERSONAL "/Applications/Stata/ado/personal/"
set rmsg on
bootstrap _b _se, reps(1000) seed(197406) nodots cluster(firmID) idcluster(newid) nowarn: boos_2sls_1_original
set rmsg off
r; t=0.00 16:02:47


Bootstrap results                                        Number of obs = 1,608
                                                         Replications  = 1,000

                                       (Replications based on 99 clusters in firmID)
------------------------------------------------------------------------------------
                   |   Observed   Bootstrap                         Normal-based
                   | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------------+----------------------------------------------------------------
b                  |
num_exper_up~m_hat |    .011584   .0074004     1.57   0.118    -.0029205    .0260885
       fr_low_prod |  -.0289046   .0274977    -1.05   0.293    -.0827991    .0249898
       u_eng_dummy |   .0640513   .0247989     2.58   0.010     .0154464    .1126563
        merchant_d |   .0253698   .0179867     1.41   0.158    -.0098835     .060623
 dlog_high_end_cap |   .0194187    .006803     2.85   0.004     .0060851    .0327522
  dlog_low_end_cap |   .0140216   .0163866     0.86   0.392    -.0180955    .0461388
    log_firm_total |  -.0297117   .0141636    -2.10   0.036    -.0574718   -.0019516
          firm_age |  -.0056414   .0018902    -2.98   0.003    -.0093461   -.0019367
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |  -.2317689   .1088958    -2.13   0.033    -.4452008    -.018337
            18942  |  -.1436358   .0836211    -1.72   0.086    -.3075302    .0202586
            18951  |  -.2202479   .0581322    -3.79   0.000    -.3341848   -.1063109
            18952  |  -.1707528   .0754805    -2.26   0.024    -.3186919   -.0228138
            18961  |  -.2633647   .0546604    -4.82   0.000    -.3704971   -.1562323
            18962  |  -.0503435    .084322    -0.60   0.550    -.2156116    .1149247
            18971  |  -.2351455   .0614537    -3.83   0.000    -.3555926   -.1146984
            18972  |  -.2469799   .0769312    -3.21   0.001    -.3977622   -.0961975
            18981  |  -.3053482   .0926905    -3.29   0.001    -.4870183   -.1236782
            18982  |  -.1615233   .0692322    -2.33   0.020    -.2972159   -.0258306
            18991  |  -.1003088   .0713606    -1.41   0.160     -.240173    .0395554
            18992  |  -.2652828   .0659644    -4.02   0.000    -.3945706    -.135995
            19001  |   -.649077   .0773658    -8.39   0.000    -.8007112   -.4974428
            19002  |  -.0583173   .0705391    -0.83   0.408    -.1965714    .0799369
            19011  |  -.1169698   .0665672    -1.76   0.079     -.247439    .0134994
            19012  |  -.0682318   .0683537    -1.00   0.318    -.2022027    .0657391
            19021  |  -.2446027   .0581234    -4.21   0.000    -.3585224    -.130683
            19022  |  -.1923108   .0705453    -2.73   0.006    -.3305771   -.0540445
            19031  |  -.2276858   .0637255    -3.57   0.000    -.3525854   -.1027861
            19032  |   -.496904   .1054649    -4.71   0.000    -.7036115   -.2901966
            19041  |  -.0445772   .0578241    -0.77   0.441    -.1579104     .068756
            19042  |    .148938   .1086669     1.37   0.171    -.0640452    .3619211
            19051  |  -.1532124   .0639916    -2.39   0.017    -.2786336   -.0277912
            19052  |  -.1231437   .0598776    -2.06   0.040    -.2405017   -.0057858
            19061  |  -.2099461   .0607615    -3.46   0.001    -.3290363   -.0908558
            19062  |  -.1155281   .0597175    -1.93   0.053    -.2325723     .001516
            19071  |  -.2254107   .0585909    -3.85   0.000    -.3402468   -.1105746
            19072  |  -.2584648   .0633395    -4.08   0.000     -.382608   -.1343217
            19081  |  -.2585993   .0635562    -4.07   0.000    -.3831671   -.1340316
            19082  |  -.0439159   .0624335    -0.70   0.482    -.1662832    .0784515
            19091  |  -.1905091   .0605747    -3.15   0.002    -.3092334   -.0717848
            19092  |  -.1563912   .0744314    -2.10   0.036    -.3022741   -.0105084
            19101  |  -.2239604   .0655147    -3.42   0.001    -.3523668   -.0955539
            19102  |  -.1076963   .0660421    -1.63   0.103    -.2371364    .0217439
            19111  |  -.1162379   .0640118    -1.82   0.069    -.2416986    .0092228
            19112  |  -.0372259   .0694718    -0.54   0.592    -.1733881    .0989364
            19121  |  -.0635743    .063682    -1.00   0.318    -.1883887    .0612401
            19122  |  -.1285104   .0644133    -2.00   0.046    -.2547583   -.0022626
            19131  |  -.1164261   .0651188    -1.79   0.074    -.2440566    .0112044
            19132  |  -.1193106   .0662039    -1.80   0.072     -.249068    .0104467
                   |
             _cons |   .5028145   .1221126     4.12   0.000     .2634783    .7421508
-------------------+----------------------------------------------------------------
se                 |
num_exper_up~m_hat |   .0102924   .0023646     4.35   0.000     .0056579    .0149269
       fr_low_prod |   .0350792   .0049319     7.11   0.000     .0254128    .0447455
       u_eng_dummy |   .0210797   .0024999     8.43   0.000       .01618    .0259793
        merchant_d |    .016509   .0017065     9.67   0.000     .0131644    .0198536
 dlog_high_end_cap |   .0072844   .0011642     6.26   0.000     .0050026    .0095663
  dlog_low_end_cap |   .0133666   .0041805     3.20   0.001     .0051731    .0215601
    log_firm_total |   .0081239   .0008885     9.14   0.000     .0063823    .0098654
          firm_age |    .001716   .0001948     8.81   0.000     .0013342    .0020978
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |   .0734757   .0082471     8.91   0.000     .0573117    .0896398
            18942  |   .0733243   .0085884     8.54   0.000     .0564913    .0901573
            18951  |   .0715124   .0081103     8.82   0.000     .0556166    .0874083
            18952  |   .0704947   .0077621     9.08   0.000     .0552812    .0857082
            18961  |   .0701267   .0076053     9.22   0.000     .0552205    .0850328
            18962  |   .0681621   .0072943     9.34   0.000     .0538656    .0824586
            18971  |   .0673713   .0068561     9.83   0.000     .0539337     .080809
            18972  |   .0670389   .0067253     9.97   0.000     .0538575    .0802202
            18981  |   .0673623   .0066524    10.13   0.000     .0543238    .0804008
            18982  |   .0661455    .006619     9.99   0.000     .0531725    .0791185
            18991  |   .0672124   .0067041    10.03   0.000     .0540725    .0803522
            18992  |   .0670286   .0066696    10.05   0.000     .0539565    .0801007
            19001  |   .0668469   .0066543    10.05   0.000     .0538048    .0798891
            19002  |   .0661103   .0066482     9.94   0.000     .0530802    .0791405
            19011  |   .0662727   .0066808     9.92   0.000     .0531786    .0793668
            19012  |   .0665646   .0067018     9.93   0.000     .0534294    .0796998
            19021  |   .0690088   .0068489    10.08   0.000     .0555851    .0824324
            19022  |   .0702242   .0072762     9.65   0.000     .0559632    .0844853
            19031  |    .071554   .0074921     9.55   0.000     .0568696    .0862383
            19032  |   .0710545   .0073121     9.72   0.000     .0567231    .0853859
            19041  |   .0705163   .0072906     9.67   0.000      .056227    .0848056
            19042  |   .0703472   .0072227     9.74   0.000     .0561911    .0845034
            19051  |   .0710427   .0070885    10.02   0.000     .0571495    .0849358
            19052  |   .0703586   .0069957    10.06   0.000     .0566473    .0840698
            19061  |   .0717094   .0071691    10.00   0.000     .0576583    .0857605
            19062  |   .0745955   .0076345     9.77   0.000     .0596322    .0895589
            19071  |    .075216    .007734     9.73   0.000     .0600577    .0903743
            19072  |   .0752294   .0077201     9.74   0.000     .0600982    .0903606
            19081  |   .0764528   .0079465     9.62   0.000      .060878    .0920276
            19082  |   .0762798   .0079304     9.62   0.000     .0607365    .0918232
            19091  |   .0770842   .0083807     9.20   0.000     .0606582    .0935101
            19092  |    .077142   .0083862     9.20   0.000     .0607052    .0935787
            19101  |   .0766161   .0082918     9.24   0.000     .0603644    .0928677
            19102  |     .07771   .0085966     9.04   0.000      .060861     .094559
            19111  |   .0787629   .0087326     9.02   0.000     .0616474    .0958784
            19112  |   .0814798   .0092549     8.80   0.000     .0633405    .0996191
            19121  |   .0807194   .0089771     8.99   0.000     .0631246    .0983143
            19122  |   .0797725   .0087639     9.10   0.000     .0625955    .0969494
            19131  |   .0794702   .0085784     9.26   0.000     .0626569    .0962835
            19132  |   .0801005   .0085179     9.40   0.000     .0634058    .0967952
                   |
             _cons |   .0813876   .0076767    10.60   0.000     .0663415    .0964337
------------------------------------------------------------------------------------
r; t=453.49 16:10:20

The same estimation results are reproduced.

The results of (4) in Table 5

The ado file we use is as follows.

program boos_2sls_2_original, eclass
version 16
tempname b V


capture drop num_exper_upgrades_st_hat num_exper_upgrades_st_cum_hat upgrade_exper_low_hat

 
 poisson num_exper_upgrades_st  c.sotan_c#c.dlog_high_end_cap fr_low_prod u_eng_dummy merchant_d ///
 dlog_high_end_cap dlog_low_end_cap log_firm_total firm_age i.year_half_year  if  est_inc==1 , robust cluster(firmID)

predict num_exper_upgrades_st_hat if e(sample)
sort firmID year_half_year
by firmID: gen num_exper_upgrades_st_cum_hat=sum(num_exper_upgrades_st_hat)
gen upgrade_exper_low_hat = num_exper_upgrades_st_cum_hat*fr_low_prod

reg dlog_firm_total num_exper_upgrades_st_cum_hat   fr_low_prod upgrade_exper_low_hat u_eng_dummy  merchant_d   dlog_high_end_cap dlog_low_end_cap ///
 log_firm_total  firm_age i.year_half_year  if  est_inc==1

matrix `b' = e(b)
matrix `V' = e(V)
ereturn post `b' `V' 
end

The following codes are to do a block bootstrap.

drop num_exper_upgrades_st_hat num_exper_upgrades_st_cum_hat 
cap drop newid
xtset, clear
quietly:xtset firmID
gen  newid = firmID
quietly:tsset newid year_half_year
quietly:keep if est_inc
sysdir set PERSONAL "/Applications/Stata/ado/personal/"
set rmsg on
bootstrap _b _se, reps(1000) seed(197406) nodots cluster(firmID) idcluster(newid) nowarn: boos_2sls_2_original
set rmsg off
r; t=0.00 16:24:32


Bootstrap results                                        Number of obs = 1,608
                                                         Replications  = 1,000

                                       (Replications based on 99 clusters in firmID)
------------------------------------------------------------------------------------
                   |   Observed   Bootstrap                         Normal-based
                   | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------------+----------------------------------------------------------------
b                  |
num_exper_up~m_hat |  -.0136359   .0087412    -1.56   0.119    -.0307683    .0034965
       fr_low_prod |  -.0804099   .0338987    -2.37   0.018    -.1468501   -.0139696
upgrade_exper_lo~t |    .081418   .0197699     4.12   0.000     .0426697    .1201663
       u_eng_dummy |   .0709999   .0253241     2.80   0.005     .0213656    .1206341
        merchant_d |   .0218151   .0189839     1.15   0.251    -.0153927    .0590229
 dlog_high_end_cap |   .0187246   .0070012     2.67   0.007     .0050024    .0324467
  dlog_low_end_cap |   .0118077   .0162206     0.73   0.467    -.0199841    .0435995
    log_firm_total |  -.0458702   .0153819    -2.98   0.003    -.0760181   -.0157222
          firm_age |  -.0089447    .002102    -4.26   0.000    -.0130645   -.0048249
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |  -.2315487   .1090091    -2.12   0.034    -.4452026   -.0178947
            18942  |  -.1509977   .0819321    -1.84   0.065    -.3115817    .0095864
            18951  |  -.2264304   .0570758    -3.97   0.000    -.3382968    -.114564
            18952  |   -.179645   .0743596    -2.42   0.016     -.325387   -.0339029
            18961  |  -.2694846   .0529201    -5.09   0.000     -.373206   -.1657632
            18962  |  -.0559701   .0835881    -0.67   0.503    -.2197999    .1078596
            18971  |  -.2358472   .0600893    -3.92   0.000    -.3536202   -.1180743
            18972  |  -.2513013   .0758327    -3.31   0.001    -.3999307   -.1026719
            18981  |  -.3068619   .0920105    -3.34   0.001    -.4871991   -.1265247
            18982  |  -.1646867   .0688441    -2.39   0.017    -.2996187   -.0297546
            18991  |   -.098971   .0701112    -1.41   0.158    -.2363863    .0384444
            18992  |  -.2624017   .0649904    -4.04   0.000    -.3897804   -.1350229
            19001  |  -.6421264   .0768054    -8.36   0.000    -.7926622   -.4915906
            19002  |  -.0607489   .0695333    -0.87   0.382    -.1970316    .0755339
            19011  |  -.1136716   .0655635    -1.73   0.083    -.2421737    .0148304
            19012  |  -.0648759   .0674915    -0.96   0.336    -.1971568     .067405
            19021  |  -.2349313   .0576239    -4.08   0.000     -.347872   -.1219905
            19022  |  -.1831559   .0707698    -2.59   0.010    -.3218621   -.0444497
            19031  |  -.2171855   .0638983    -3.40   0.001    -.3424238   -.0919472
            19032  |  -.4896982   .1049375    -4.67   0.000     -.695372   -.2840245
            19041  |  -.0418287   .0578407    -0.72   0.470    -.1551945     .071537
            19042  |   .1523369   .1080407     1.41   0.159     -.059419    .3640928
            19051  |  -.1411425   .0642063    -2.20   0.028    -.2669846   -.0153005
            19052  |  -.1094506   .0601442    -1.82   0.069    -.2273311      .00843
            19061  |  -.1917889   .0603472    -3.18   0.001    -.3100673   -.0735105
            19062  |  -.0970968   .0593456    -1.64   0.102     -.213412    .0192184
            19071  |  -.2046371   .0583906    -3.50   0.000    -.3190806   -.0901936
            19072  |  -.2377659    .063074    -3.77   0.000    -.3613886   -.1141431
            19081  |  -.2402924   .0629556    -3.82   0.000    -.3636832   -.1169016
            19082  |   -.028004   .0617743    -0.45   0.650    -.1490794    .0930714
            19091  |  -.1711682    .060882    -2.81   0.005    -.2904948   -.0518416
            19092  |   -.141601   .0736876    -1.92   0.055    -.2860262    .0028241
            19101  |  -.2078389   .0656235    -3.17   0.002    -.3364585   -.0792192
            19102  |  -.0954905   .0655307    -1.46   0.145    -.2239283    .0329473
            19111  |  -.0968287   .0646594    -1.50   0.134    -.2235588    .0299015
            19112  |  -.0166007   .0697452    -0.24   0.812    -.1532987    .1200973
            19121  |  -.0365185   .0649846    -0.56   0.574     -.163886     .090849
            19122  |   -.099508   .0660866    -1.51   0.132    -.2290354    .0300193
            19131  |  -.0824395   .0668156    -1.23   0.217    -.2133957    .0485166
            19132  |  -.0818231   .0679207    -1.20   0.228    -.2149452    .0512991
                   |
             _cons |   .6813047   .1364541     4.99   0.000     .4138596    .9487499
-------------------+----------------------------------------------------------------
se                 |
num_exper_up~m_hat |   .0123694   .0047561     2.60   0.009     .0030476    .0216911
       fr_low_prod |   .0376921   .0062059     6.07   0.000     .0255288    .0498554
upgrade_exper_lo~t |   .0223423   .0064298     3.47   0.001     .0097402    .0349444
       u_eng_dummy |   .0210835   .0025112     8.40   0.000     .0161617    .0260053
        merchant_d |   .0164733    .001711     9.63   0.000     .0131198    .0198267
 dlog_high_end_cap |   .0072584   .0011591     6.26   0.000     .0049865    .0095303
  dlog_low_end_cap |   .0133281   .0041748     3.19   0.001     .0051458    .0215105
    log_firm_total |   .0092273   .0009792     9.42   0.000      .007308    .0111465
          firm_age |   .0019348   .0002109     9.17   0.000     .0015214    .0023481
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |   .0731881   .0082139     8.91   0.000     .0570891    .0892871
            18942  |   .0730652   .0085599     8.54   0.000     .0562882    .0898422
            18951  |   .0712527   .0080819     8.82   0.000     .0554124    .0870929
            18952  |   .0702611   .0077366     9.08   0.000     .0550976    .0854246
            18961  |   .0698723   .0075797     9.22   0.000     .0550163    .0847283
            18962  |   .0679128   .0072679     9.34   0.000      .053668    .0821577
            18971  |   .0671078   .0068271     9.83   0.000     .0537271    .0804886
            18972  |   .0667869   .0067011     9.97   0.000     .0536531    .0799208
            18981  |   .0670998   .0066254    10.13   0.000     .0541142    .0800855
            18982  |   .0658923   .0065927     9.99   0.000     .0529708    .0788138
            18991  |   .0669502   .0066785    10.02   0.000     .0538607    .0800398
            18992  |   .0667709   .0066441    10.05   0.000     .0537486    .0797932
            19001  |   .0666125   .0066288    10.05   0.000     .0536203    .0796048
            19002  |   .0658549   .0066228     9.94   0.000     .0528745    .0788353
            19011  |   .0660194   .0066548     9.92   0.000     .0529761    .0790626
            19012  |   .0663104   .0066754     9.93   0.000     .0532269    .0793939
            19021  |   .0687898   .0068287    10.07   0.000     .0554057    .0821739
            19022  |   .0699944   .0072536     9.65   0.000     .0557776    .0842111
            19031  |    .071332   .0074687     9.55   0.000     .0566937    .0859704
            19032  |   .0708039   .0072865     9.72   0.000     .0565227    .0850852
            19041  |   .0702443   .0072652     9.67   0.000     .0560047    .0844839
            19042  |    .070078   .0071979     9.74   0.000     .0559704    .0841856
            19051  |    .070842   .0070632    10.03   0.000     .0569984    .0846856
            19052  |   .0701838   .0069713    10.07   0.000     .0565202    .0838473
            19061  |   .0716022   .0071458    10.02   0.000     .0575966    .0856078
            19062  |   .0744754   .0076107     9.79   0.000     .0595587    .0893922
            19071  |   .0751381   .0077052     9.75   0.000     .0600362      .09024
            19072  |   .0751498   .0076866     9.78   0.000     .0600844    .0902153
            19081  |    .076319    .007911     9.65   0.000     .0608138    .0918242
            19082  |   .0761066   .0078995     9.63   0.000     .0606238    .0915893
            19091  |   .0769656    .008351     9.22   0.000     .0605978    .0933333
            19092  |    .076947   .0083608     9.20   0.000     .0605602    .0933339
            19101  |   .0764442   .0082618     9.25   0.000     .0602515     .092637
            19102  |   .0774782   .0085649     9.05   0.000     .0606913    .0942651
            19111  |   .0786351   .0086977     9.04   0.000      .061588    .0956822
            19112  |   .0813579   .0092231     8.82   0.000     .0632809     .099435
            19121  |   .0807455   .0089422     9.03   0.000     .0632191    .0982719
            19122  |   .0798577   .0087262     9.15   0.000     .0627547    .0969607
            19131  |   .0797066   .0085406     9.33   0.000     .0629674    .0964458
            19132  |   .0804473   .0084865     9.48   0.000     .0638141    .0970805
                   |
             _cons |   .0947167   .0089509    10.58   0.000     .0771732    .1122601
------------------------------------------------------------------------------------
r; t=467.38 16:32:19

The same estimation results are reproduced.

Our corrected estimation results

The results of (3) in Table 5

We use the corrected ado file. In the corrected file, firmID is replaced by newid.

program boos_2sls_1_modified, eclass
version 16
tempname b V
*tempvar num_exper_upgrades_st_hat 
*tempvar num_exper_upgrades_st_cum_hat

capture drop num_exper_upgrades_st_hat num_exper_upgrades_st_cum_hat

poisson num_exper_upgrades_st  c.sotan_c#c.dlog_high_end_cap fr_low_prod u_eng_dummy  merchant_d ///
dlog_high_end_cap dlog_low_end_cap log_firm_total firm_age i.year_half_year  if est_inc==1 , robust cluster(firmID)


 
predict num_exper_upgrades_st_hat if e(sample)
sort newid year_half_year
by newid: gen num_exper_upgrades_st_cum_hat=sum(num_exper_upgrades_st_hat)

reg dlog_firm_total num_exper_upgrades_st_cum_hat  fr_low_prod   u_eng_dummy  merchant_d  ///
dlog_high_end_cap dlog_low_end_cap   log_firm_total  firm_age i.year_half_year  if  est_inc==1


matrix `b' = e(b)
matrix `V' = e(V)
ereturn post `b' `V' 
end
d

The following codes are to do a block bootstrap using the corrected ado file.

cap drop newid
xtset, clear
quietly:xtset firmID
gen  newid = firmID
quietly:tsset newid year_half_year
quietly:keep if est_inc
sysdir set PERSONAL "/Applications/Stata/ado/personal/"
set rmsg on
bootstrap _b _se, reps(1000) seed(197406) nodots cluster(firmID) idcluster(newid) nowarn: boos_2sls_1_modified
set rmsg off
r; t=0.00 17:00:35


Bootstrap results                                        Number of obs = 1,608
                                                         Replications  = 1,000

                                       (Replications based on 99 clusters in firmID)
------------------------------------------------------------------------------------
                   |   Observed   Bootstrap                         Normal-based
                   | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------------+----------------------------------------------------------------
b                  |
num_exper_up~m_hat |    .011584   .0115483     1.00   0.316    -.0110503    .0342182
       fr_low_prod |  -.0289046   .0284083    -1.02   0.309    -.0845838    .0267745
       u_eng_dummy |   .0640513   .0249542     2.57   0.010      .015142    .1129606
        merchant_d |   .0253698   .0182248     1.39   0.164    -.0103501    .0610896
 dlog_high_end_cap |   .0194187   .0067558     2.87   0.004     .0061775    .0326598
  dlog_low_end_cap |   .0140216    .016539     0.85   0.397    -.0183941    .0464374
    log_firm_total |  -.0297117   .0150901    -1.97   0.049    -.0592877   -.0001357
          firm_age |  -.0056414   .0020315    -2.78   0.005     -.009623   -.0016598
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |  -.2317689   .1090228    -2.13   0.034    -.4454497   -.0180882
            18942  |  -.1436358   .0838155    -1.71   0.087    -.3079111    .0206395
            18951  |  -.2202479   .0584364    -3.77   0.000    -.3347811   -.1057146
            18952  |  -.1707528   .0757536    -2.25   0.024    -.3192272   -.0222785
            18961  |  -.2633647   .0548826    -4.80   0.000    -.3709326   -.1557967
            18962  |  -.0503435   .0843317    -0.60   0.551    -.2156306    .1149437
            18971  |  -.2351455   .0616137    -3.82   0.000    -.3559062   -.1143848
            18972  |  -.2469799   .0769269    -3.21   0.001    -.3977539   -.0962058
            18981  |  -.3053482   .0928834    -3.29   0.001    -.4873963   -.1233002
            18982  |  -.1615233   .0693215    -2.33   0.020    -.2973909   -.0256556
            18991  |  -.1003088   .0715964    -1.40   0.161    -.2406351    .0400176
            18992  |  -.2652828   .0660639    -4.02   0.000    -.3947657   -.1357999
            19001  |   -.649077    .077672    -8.36   0.000    -.8013113   -.4968427
            19002  |  -.0583173   .0707663    -0.82   0.410    -.1970167    .0803822
            19011  |  -.1169698   .0667382    -1.75   0.080    -.2477743    .0138347
            19012  |  -.0682318    .068608    -0.99   0.320     -.202701    .0662374
            19021  |  -.2446027    .058215    -4.20   0.000    -.3587019   -.1305034
            19022  |  -.1923108   .0705746    -2.72   0.006    -.3306344   -.0539871
            19031  |  -.2276858   .0638652    -3.57   0.000    -.3528592   -.1025124
            19032  |   -.496904   .1053347    -4.72   0.000    -.7033563   -.2904517
            19041  |  -.0445772   .0579341    -0.77   0.442     -.158126    .0689716
            19042  |    .148938   .1085848     1.37   0.170    -.0638843    .3617602
            19051  |  -.1532124   .0639811    -2.39   0.017     -.278613   -.0278117
            19052  |  -.1231437   .0600201    -2.05   0.040     -.240781   -.0055064
            19061  |  -.2099461    .060778    -3.45   0.001    -.3290687   -.0908234
            19062  |  -.1155281   .0599645    -1.93   0.054    -.2330563        .002
            19071  |  -.2254107    .058705    -3.84   0.000    -.3404704    -.110351
            19072  |  -.2584648   .0637141    -4.06   0.000    -.3833423   -.1335874
            19081  |  -.2585993   .0636831    -4.06   0.000    -.3834159   -.1337828
            19082  |  -.0439159   .0624821    -0.70   0.482    -.1663786    .0785468
            19091  |  -.1905091   .0605654    -3.15   0.002    -.3092151   -.0718032
            19092  |  -.1563912   .0748209    -2.09   0.037    -.3030375   -.0097449
            19101  |  -.2239604   .0658515    -3.40   0.001    -.3530269   -.0948938
            19102  |  -.1076963   .0667224    -1.61   0.107    -.2384697    .0230772
            19111  |  -.1162379   .0643589    -1.81   0.071    -.2423791    .0099033
            19112  |  -.0372259   .0697381    -0.53   0.593    -.1739101    .0994584
            19121  |  -.0635743   .0637459    -1.00   0.319    -.1885139    .0613653
            19122  |  -.1285104   .0642467    -2.00   0.045    -.2544316   -.0025892
            19131  |  -.1164261   .0652337    -1.78   0.074    -.2442819    .0114296
            19132  |  -.1193106   .0658581    -1.81   0.070    -.2483901    .0097688
                   |
             _cons |   .5028145   .1261369     3.99   0.000     .2555908    .7500383
-------------------+----------------------------------------------------------------
se                 |
num_exper_up~m_hat |   .0102924   .0026386     3.90   0.000     .0051209    .0154639
       fr_low_prod |   .0350792   .0052512     6.68   0.000     .0247869    .0453714
       u_eng_dummy |   .0210797   .0024966     8.44   0.000     .0161863     .025973
        merchant_d |    .016509   .0016832     9.81   0.000     .0132099     .019808
 dlog_high_end_cap |   .0072844   .0011647     6.25   0.000     .0050016    .0095672
  dlog_low_end_cap |   .0133666   .0041829     3.20   0.001     .0051683    .0215649
    log_firm_total |   .0081239   .0009311     8.73   0.000      .006299    .0099487
          firm_age |    .001716   .0002068     8.30   0.000     .0013107    .0021213
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |   .0734757   .0082405     8.92   0.000     .0573245    .0896269
            18942  |   .0733243   .0085833     8.54   0.000     .0565013    .0901474
            18951  |   .0715124   .0081062     8.82   0.000     .0556245    .0874004
            18952  |   .0704947   .0077577     9.09   0.000       .05529    .0856995
            18961  |   .0701267   .0076001     9.23   0.000     .0552307    .0850226
            18962  |   .0681621   .0072897     9.35   0.000     .0538746    .0824496
            18971  |   .0673713   .0068513     9.83   0.000      .053943    .0807997
            18972  |   .0670389   .0067211     9.97   0.000     .0538658    .0802119
            18981  |   .0673623   .0066486    10.13   0.000     .0543313    .0803933
            18982  |   .0661455   .0066159    10.00   0.000     .0531787    .0791124
            18991  |   .0672124   .0067014    10.03   0.000     .0540778    .0803469
            18992  |   .0670286   .0066669    10.05   0.000     .0539617    .0800955
            19001  |   .0668469    .006653    10.05   0.000     .0538072    .0798866
            19002  |   .0661103    .006645     9.95   0.000     .0530864    .0791343
            19011  |   .0662727     .00668     9.92   0.000     .0531802    .0793651
            19012  |   .0665646   .0066996     9.94   0.000     .0534337    .0796955
            19021  |   .0690088   .0068489    10.08   0.000     .0555852    .0824324
            19022  |   .0702242   .0072736     9.65   0.000     .0559683    .0844802
            19031  |    .071554   .0074895     9.55   0.000     .0568748    .0862331
            19032  |   .0710545   .0073078     9.72   0.000     .0567314    .0853776
            19041  |   .0705163   .0072858     9.68   0.000     .0562364    .0847963
            19042  |   .0703472   .0072178     9.75   0.000     .0562005    .0844939
            19051  |   .0710427   .0070847    10.03   0.000     .0571569    .0849285
            19052  |   .0703586    .006992    10.06   0.000     .0566545    .0840626
            19061  |   .0717094    .007165    10.01   0.000     .0576663    .0857525
            19062  |   .0745955   .0076286     9.78   0.000     .0596437    .0895473
            19071  |    .075216   .0077298     9.73   0.000     .0600658    .0903662
            19072  |   .0752294   .0077164     9.75   0.000     .0601055    .0903533
            19081  |   .0764528   .0079403     9.63   0.000     .0608901    .0920155
            19082  |   .0762798   .0079241     9.63   0.000     .0607489    .0918108
            19091  |   .0770842   .0083698     9.21   0.000     .0606797    .0934886
            19092  |    .077142   .0083779     9.21   0.000     .0607215    .0935624
            19101  |   .0766161   .0082852     9.25   0.000     .0603775    .0928547
            19102  |     .07771   .0085889     9.05   0.000     .0608761    .0945438
            19111  |   .0787629   .0087238     9.03   0.000     .0616646    .0958612
            19112  |   .0814798   .0092431     8.82   0.000     .0633636     .099596
            19121  |   .0807194   .0089631     9.01   0.000      .063152    .0982868
            19122  |   .0797725   .0087554     9.11   0.000     .0626123    .0969326
            19131  |   .0794702   .0085687     9.27   0.000     .0626759    .0962645
            19132  |   .0801005   .0085059     9.42   0.000     .0634293    .0967717
                   |
             _cons |   .0813876   .0078062    10.43   0.000     .0660877    .0966875
------------------------------------------------------------------------------------
r; t=458.85 17:08:14

The results of (4) in Table 5

The corrected ado file is as follows.

program boos_2sls_2_modified, eclass
version 16
tempname b V


capture drop num_exper_upgrades_st_hat num_exper_upgrades_st_cum_hat upgrade_exper_low_hat

 
 poisson num_exper_upgrades_st  c.sotan_c#c.dlog_high_end_cap fr_low_prod u_eng_dummy merchant_d ///
 dlog_high_end_cap dlog_low_end_cap log_firm_total firm_age i.year_half_year  if  est_inc==1 , robust cluster(firmID)

predict num_exper_upgrades_st_hat if e(sample)
sort newid year_half_year
by newid: gen num_exper_upgrades_st_cum_hat=sum(num_exper_upgrades_st_hat)
gen upgrade_exper_low_hat = num_exper_upgrades_st_cum_hat*fr_low_prod

reg dlog_firm_total num_exper_upgrades_st_cum_hat   fr_low_prod upgrade_exper_low_hat u_eng_dummy  merchant_d   dlog_high_end_cap dlog_low_end_cap ///
 log_firm_total  firm_age i.year_half_year  if  est_inc==1

matrix `b' = e(b)
matrix `V' = e(V)
ereturn post `b' `V' 
end

The following codes are to do a block bootstrap using the corrected ado file.

drop num_exper_upgrades_st_hat num_exper_upgrades_st_cum_hat upgrade_exper_low_hat
cap drop newid
xtset, clear
quietly:xtset firmID
gen  newid = firmID
quietly:tsset newid year_half_year
quietly:keep if est_inc
sysdir set PERSONAL "/Applications/Stata/ado/personal/"
set rmsg on
bootstrap _b _se, reps(1000) seed(197406) nodots cluster(firmID) idcluster(newid) nowarn: boos_2sls_2_modified
set rmsg off
r; t=0.00 17:50:31


Bootstrap results                                        Number of obs = 1,608
                                                         Replications  = 1,000

                                       (Replications based on 99 clusters in firmID)
------------------------------------------------------------------------------------
                   |   Observed   Bootstrap                         Normal-based
                   | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------------+----------------------------------------------------------------
b                  |
num_exper_up~m_hat |  -.0136359    .013527    -1.01   0.313    -.0401483    .0128765
       fr_low_prod |  -.0804099   .0352664    -2.28   0.023    -.1495306   -.0112891
upgrade_exper_lo~t |    .081418   .0340635     2.39   0.017     .0146548    .1481812
       u_eng_dummy |   .0709999   .0266415     2.67   0.008     .0187834    .1232163
        merchant_d |   .0218151    .019978     1.09   0.275    -.0173411    .0609712
 dlog_high_end_cap |   .0187246    .006934     2.70   0.007     .0051343    .0323149
  dlog_low_end_cap |   .0118077   .0160006     0.74   0.461     -.019553    .0431683
    log_firm_total |  -.0458702   .0182134    -2.52   0.012    -.0815677   -.0101726
          firm_age |  -.0089447    .002656    -3.37   0.001    -.0141504    -.003739
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |  -.2315487   .1092369    -2.12   0.034    -.4456491   -.0174483
            18942  |  -.1509977   .0820268    -1.84   0.066    -.3117673     .009772
            18951  |  -.2264304   .0577743    -3.92   0.000     -.339666   -.1131948
            18952  |   -.179645   .0744597    -2.41   0.016    -.3255834   -.0337066
            18961  |  -.2694846    .053507    -5.04   0.000    -.3743564   -.1646128
            18962  |  -.0559701   .0834335    -0.67   0.502    -.2194969    .1075566
            18971  |  -.2358472   .0603963    -3.90   0.000    -.3542218   -.1174727
            18972  |  -.2513013   .0757621    -3.32   0.001    -.3997923   -.1028103
            18981  |  -.3068619   .0924291    -3.32   0.001    -.4880197   -.1257041
            18982  |  -.1646867   .0689877    -2.39   0.017       -.2999   -.0294733
            18991  |   -.098971   .0703185    -1.41   0.159    -.2367927    .0388508
            18992  |  -.2624017   .0649865    -4.04   0.000    -.3897729   -.1350305
            19001  |  -.6421264   .0773704    -8.30   0.000    -.7937695   -.4904833
            19002  |  -.0607489    .070182    -0.87   0.387    -.1983031    .0768054
            19011  |  -.1136716   .0658935    -1.73   0.085    -.2428204    .0154771
            19012  |  -.0648759   .0679492    -0.95   0.340    -.1980539     .068302
            19021  |  -.2349313   .0580572    -4.05   0.000    -.3487213   -.1211412
            19022  |  -.1831559   .0713461    -2.57   0.010    -.3229918   -.0433201
            19031  |  -.2171855   .0642965    -3.38   0.001    -.3432044   -.0911667
            19032  |  -.4896982   .1043097    -4.69   0.000    -.6941415   -.2852549
            19041  |  -.0418287   .0582154    -0.72   0.472    -.1559288    .0722714
            19042  |   .1523369   .1076383     1.42   0.157    -.0586303    .3633041
            19051  |  -.1411425   .0644141    -2.19   0.028    -.2673918   -.0148933
            19052  |  -.1094506   .0607772    -1.80   0.072    -.2285718    .0096706
            19061  |  -.1917889   .0611768    -3.13   0.002    -.3116933   -.0718845
            19062  |  -.0970968   .0607212    -1.60   0.110    -.2161082    .0219146
            19071  |  -.2046371   .0598543    -3.42   0.001    -.3219494   -.0873249
            19072  |  -.2377659   .0646629    -3.68   0.000    -.3645028   -.1110289
            19081  |  -.2402924   .0641145    -3.75   0.000    -.3659546   -.1146302
            19082  |   -.028004   .0619641    -0.45   0.651    -.1494513    .0934434
            19091  |  -.1711682    .061139    -2.80   0.005    -.2909985   -.0513379
            19092  |   -.141601   .0745523    -1.90   0.058    -.2877209    .0045189
            19101  |  -.2078389   .0671255    -3.10   0.002    -.3394024   -.0762753
            19102  |  -.0954905   .0665397    -1.44   0.151     -.225906     .034925
            19111  |  -.0968287   .0662731    -1.46   0.144    -.2267215    .0330641
            19112  |  -.0166007   .0715186    -0.23   0.816    -.1567745    .1235732
            19121  |  -.0365185   .0670752    -0.54   0.586    -.1679834    .0949464
            19122  |   -.099508   .0671677    -1.48   0.138    -.2311543    .0321382
            19131  |  -.0824395   .0690757    -1.19   0.233    -.2178255    .0529464
            19132  |  -.0818231   .0698396    -1.17   0.241    -.2187063    .0550601
                   |
             _cons |   .6813047   .1582127     4.31   0.000     .3712135     .991396
-------------------+----------------------------------------------------------------
se                 |
num_exper_up~m_hat |   .0123694   .0063982     1.93   0.053     -.000171    .0249097
       fr_low_prod |   .0376921   .0060403     6.24   0.000     .0258534    .0495308
upgrade_exper_lo~t |   .0223423   .0092527     2.41   0.016     .0042073    .0404773
       u_eng_dummy |   .0210835   .0025002     8.43   0.000     .0161833    .0259838
        merchant_d |   .0164733   .0016729     9.85   0.000     .0131944    .0197521
 dlog_high_end_cap |   .0072584   .0011597     6.26   0.000     .0049855    .0095313
  dlog_low_end_cap |   .0133281   .0041717     3.19   0.001     .0051518    .0215045
    log_firm_total |   .0092273   .0010669     8.65   0.000     .0071362    .0113184
          firm_age |   .0019348   .0002394     8.08   0.000     .0014656    .0024039
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |   .0731881   .0081864     8.94   0.000     .0571429    .0892332
            18942  |   .0730652   .0085341     8.56   0.000     .0563386    .0897918
            18951  |   .0712527   .0080583     8.84   0.000     .0554588    .0870465
            18952  |   .0702611   .0077128     9.11   0.000     .0551443     .085378
            18961  |   .0698723   .0075546     9.25   0.000     .0550655    .0846791
            18962  |   .0679128    .007244     9.38   0.000     .0537149    .0821107
            18971  |   .0671078   .0068042     9.86   0.000      .053772    .0804437
            18972  |   .0667869   .0066798    10.00   0.000     .0536947    .0798792
            18981  |   .0670998   .0066067    10.16   0.000     .0541509    .0800488
            18982  |   .0658923   .0065766    10.02   0.000     .0530023    .0787823
            18991  |   .0669502   .0066612    10.05   0.000     .0538945    .0800059
            18992  |   .0667709   .0066267    10.08   0.000     .0537827    .0797591
            19001  |   .0666125   .0066144    10.07   0.000     .0536486    .0795765
            19002  |   .0658549   .0066065     9.97   0.000     .0529064    .0788034
            19011  |   .0660194    .006641     9.94   0.000     .0530034    .0790354
            19012  |   .0663104   .0066592     9.96   0.000     .0532586    .0793621
            19021  |   .0687898   .0068146    10.09   0.000     .0554334    .0821462
            19022  |   .0699944   .0072379     9.67   0.000     .0558084    .0841803
            19031  |    .071332    .007452     9.57   0.000     .0567264    .0859377
            19032  |   .0708039   .0072708     9.74   0.000     .0565534    .0850545
            19041  |   .0702443   .0072499     9.69   0.000     .0560347    .0844538
            19042  |    .070078   .0071817     9.76   0.000      .056002    .0841539
            19051  |    .070842   .0070477    10.05   0.000     .0570288    .0846552
            19052  |   .0701838   .0069518    10.10   0.000     .0565586     .083809
            19061  |   .0716022   .0071259    10.05   0.000     .0576358    .0855687
            19062  |   .0744754   .0075888     9.81   0.000     .0596017    .0893491
            19071  |   .0751381   .0076813     9.78   0.000      .060083    .0901932
            19072  |   .0751498   .0076653     9.80   0.000     .0601261    .0901736
            19081  |    .076319   .0078871     9.68   0.000     .0608605    .0917775
            19082  |   .0761066   .0078767     9.66   0.000     .0606684    .0915447
            19091  |   .0769656   .0083193     9.25   0.000       .06066    .0932711
            19092  |    .076947   .0083305     9.24   0.000     .0606195    .0932746
            19101  |   .0764442   .0082333     9.28   0.000     .0603073    .0925812
            19102  |   .0774782   .0085371     9.08   0.000     .0607457    .0942106
            19111  |   .0786351   .0086645     9.08   0.000      .061653    .0956172
            19112  |   .0813579    .009187     8.86   0.000     .0633517    .0993641
            19121  |   .0807455   .0089034     9.07   0.000      .063295    .0981959
            19122  |   .0798577    .008695     9.18   0.000     .0628157    .0968997
            19131  |   .0797066   .0085051     9.37   0.000     .0630369    .0963763
            19132  |   .0804473   .0084515     9.52   0.000     .0638826     .097012
                   |
             _cons |   .0947167   .0090575    10.46   0.000     .0769643    .1124691
------------------------------------------------------------------------------------
r; t=525.66 17:59:17

Results side by side

Column (3) in Table 5

Original estimation results

sysdir set PERSONAL "/Applications/Stata/ado/personal/"
set rmsg on
bootstrap _b _se, reps(1000) seed(197406) nodots cluster(firmID) idcluster(newid) nowarn: boos_2sls_1_original
set rmsg off
r; t=0.00 18:29:09


Bootstrap results                                        Number of obs = 1,608
                                                         Replications  = 1,000

                                       (Replications based on 99 clusters in firmID)
------------------------------------------------------------------------------------
                   |   Observed   Bootstrap                         Normal-based
                   | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------------+----------------------------------------------------------------
b                  |
num_exper_up~m_hat |    .011584   .0074004     1.57   0.118    -.0029205    .0260885
       fr_low_prod |  -.0289046   .0274977    -1.05   0.293    -.0827991    .0249898
       u_eng_dummy |   .0640513   .0247989     2.58   0.010     .0154464    .1126563
        merchant_d |   .0253698   .0179867     1.41   0.158    -.0098835     .060623
 dlog_high_end_cap |   .0194187    .006803     2.85   0.004     .0060851    .0327522
  dlog_low_end_cap |   .0140216   .0163866     0.86   0.392    -.0180955    .0461388
    log_firm_total |  -.0297117   .0141636    -2.10   0.036    -.0574718   -.0019516
          firm_age |  -.0056414   .0018902    -2.98   0.003    -.0093461   -.0019367
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |  -.2317689   .1088958    -2.13   0.033    -.4452008    -.018337
            18942  |  -.1436358   .0836211    -1.72   0.086    -.3075302    .0202586
            18951  |  -.2202479   .0581322    -3.79   0.000    -.3341848   -.1063109
            18952  |  -.1707528   .0754805    -2.26   0.024    -.3186919   -.0228138
            18961  |  -.2633647   .0546604    -4.82   0.000    -.3704971   -.1562323
            18962  |  -.0503435    .084322    -0.60   0.550    -.2156116    .1149247
            18971  |  -.2351455   .0614537    -3.83   0.000    -.3555926   -.1146984
            18972  |  -.2469799   .0769312    -3.21   0.001    -.3977622   -.0961975
            18981  |  -.3053482   .0926905    -3.29   0.001    -.4870183   -.1236782
            18982  |  -.1615233   .0692322    -2.33   0.020    -.2972159   -.0258306
            18991  |  -.1003088   .0713606    -1.41   0.160     -.240173    .0395554
            18992  |  -.2652828   .0659644    -4.02   0.000    -.3945706    -.135995
            19001  |   -.649077   .0773658    -8.39   0.000    -.8007112   -.4974428
            19002  |  -.0583173   .0705391    -0.83   0.408    -.1965714    .0799369
            19011  |  -.1169698   .0665672    -1.76   0.079     -.247439    .0134994
            19012  |  -.0682318   .0683537    -1.00   0.318    -.2022027    .0657391
            19021  |  -.2446027   .0581234    -4.21   0.000    -.3585224    -.130683
            19022  |  -.1923108   .0705453    -2.73   0.006    -.3305771   -.0540445
            19031  |  -.2276858   .0637255    -3.57   0.000    -.3525854   -.1027861
            19032  |   -.496904   .1054649    -4.71   0.000    -.7036115   -.2901966
            19041  |  -.0445772   .0578241    -0.77   0.441    -.1579104     .068756
            19042  |    .148938   .1086669     1.37   0.171    -.0640452    .3619211
            19051  |  -.1532124   .0639916    -2.39   0.017    -.2786336   -.0277912
            19052  |  -.1231437   .0598776    -2.06   0.040    -.2405017   -.0057858
            19061  |  -.2099461   .0607615    -3.46   0.001    -.3290363   -.0908558
            19062  |  -.1155281   .0597175    -1.93   0.053    -.2325723     .001516
            19071  |  -.2254107   .0585909    -3.85   0.000    -.3402468   -.1105746
            19072  |  -.2584648   .0633395    -4.08   0.000     -.382608   -.1343217
            19081  |  -.2585993   .0635562    -4.07   0.000    -.3831671   -.1340316
            19082  |  -.0439159   .0624335    -0.70   0.482    -.1662832    .0784515
            19091  |  -.1905091   .0605747    -3.15   0.002    -.3092334   -.0717848
            19092  |  -.1563912   .0744314    -2.10   0.036    -.3022741   -.0105084
            19101  |  -.2239604   .0655147    -3.42   0.001    -.3523668   -.0955539
            19102  |  -.1076963   .0660421    -1.63   0.103    -.2371364    .0217439
            19111  |  -.1162379   .0640118    -1.82   0.069    -.2416986    .0092228
            19112  |  -.0372259   .0694718    -0.54   0.592    -.1733881    .0989364
            19121  |  -.0635743    .063682    -1.00   0.318    -.1883887    .0612401
            19122  |  -.1285104   .0644133    -2.00   0.046    -.2547583   -.0022626
            19131  |  -.1164261   .0651188    -1.79   0.074    -.2440566    .0112044
            19132  |  -.1193106   .0662039    -1.80   0.072     -.249068    .0104467
                   |
             _cons |   .5028145   .1221126     4.12   0.000     .2634783    .7421508
-------------------+----------------------------------------------------------------
se                 |
num_exper_up~m_hat |   .0102924   .0023646     4.35   0.000     .0056579    .0149269
       fr_low_prod |   .0350792   .0049319     7.11   0.000     .0254128    .0447455
       u_eng_dummy |   .0210797   .0024999     8.43   0.000       .01618    .0259793
        merchant_d |    .016509   .0017065     9.67   0.000     .0131644    .0198536
 dlog_high_end_cap |   .0072844   .0011642     6.26   0.000     .0050026    .0095663
  dlog_low_end_cap |   .0133666   .0041805     3.20   0.001     .0051731    .0215601
    log_firm_total |   .0081239   .0008885     9.14   0.000     .0063823    .0098654
          firm_age |    .001716   .0001948     8.81   0.000     .0013342    .0020978
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |   .0734757   .0082471     8.91   0.000     .0573117    .0896398
            18942  |   .0733243   .0085884     8.54   0.000     .0564913    .0901573
            18951  |   .0715124   .0081103     8.82   0.000     .0556166    .0874083
            18952  |   .0704947   .0077621     9.08   0.000     .0552812    .0857082
            18961  |   .0701267   .0076053     9.22   0.000     .0552205    .0850328
            18962  |   .0681621   .0072943     9.34   0.000     .0538656    .0824586
            18971  |   .0673713   .0068561     9.83   0.000     .0539337     .080809
            18972  |   .0670389   .0067253     9.97   0.000     .0538575    .0802202
            18981  |   .0673623   .0066524    10.13   0.000     .0543238    .0804008
            18982  |   .0661455    .006619     9.99   0.000     .0531725    .0791185
            18991  |   .0672124   .0067041    10.03   0.000     .0540725    .0803522
            18992  |   .0670286   .0066696    10.05   0.000     .0539565    .0801007
            19001  |   .0668469   .0066543    10.05   0.000     .0538048    .0798891
            19002  |   .0661103   .0066482     9.94   0.000     .0530802    .0791405
            19011  |   .0662727   .0066808     9.92   0.000     .0531786    .0793668
            19012  |   .0665646   .0067018     9.93   0.000     .0534294    .0796998
            19021  |   .0690088   .0068489    10.08   0.000     .0555851    .0824324
            19022  |   .0702242   .0072762     9.65   0.000     .0559632    .0844853
            19031  |    .071554   .0074921     9.55   0.000     .0568696    .0862383
            19032  |   .0710545   .0073121     9.72   0.000     .0567231    .0853859
            19041  |   .0705163   .0072906     9.67   0.000      .056227    .0848056
            19042  |   .0703472   .0072227     9.74   0.000     .0561911    .0845034
            19051  |   .0710427   .0070885    10.02   0.000     .0571495    .0849358
            19052  |   .0703586   .0069957    10.06   0.000     .0566473    .0840698
            19061  |   .0717094   .0071691    10.00   0.000     .0576583    .0857605
            19062  |   .0745955   .0076345     9.77   0.000     .0596322    .0895589
            19071  |    .075216    .007734     9.73   0.000     .0600577    .0903743
            19072  |   .0752294   .0077201     9.74   0.000     .0600982    .0903606
            19081  |   .0764528   .0079465     9.62   0.000      .060878    .0920276
            19082  |   .0762798   .0079304     9.62   0.000     .0607365    .0918232
            19091  |   .0770842   .0083807     9.20   0.000     .0606582    .0935101
            19092  |    .077142   .0083862     9.20   0.000     .0607052    .0935787
            19101  |   .0766161   .0082918     9.24   0.000     .0603644    .0928677
            19102  |     .07771   .0085966     9.04   0.000      .060861     .094559
            19111  |   .0787629   .0087326     9.02   0.000     .0616474    .0958784
            19112  |   .0814798   .0092549     8.80   0.000     .0633405    .0996191
            19121  |   .0807194   .0089771     8.99   0.000     .0631246    .0983143
            19122  |   .0797725   .0087639     9.10   0.000     .0625955    .0969494
            19131  |   .0794702   .0085784     9.26   0.000     .0626569    .0962835
            19132  |   .0801005   .0085179     9.40   0.000     .0634058    .0967952
                   |
             _cons |   .0813876   .0076767    10.60   0.000     .0663415    .0964337
------------------------------------------------------------------------------------
r; t=472.33 18:37:01

Corrected estimation results

sysdir set PERSONAL "/Applications/Stata/ado/personal/"
set rmsg on
bootstrap _b _se, reps(1000) seed(197406) nodots cluster(firmID) idcluster(newid) nowarn: boos_2sls_1_modified
set rmsg off
r; t=0.00 19:48:46


Bootstrap results                                        Number of obs = 1,608
                                                         Replications  = 1,000

                                       (Replications based on 99 clusters in firmID)
------------------------------------------------------------------------------------
                   |   Observed   Bootstrap                         Normal-based
                   | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------------+----------------------------------------------------------------
b                  |
num_exper_up~m_hat |    .011584   .0115483     1.00   0.316    -.0110503    .0342182
       fr_low_prod |  -.0289046   .0284083    -1.02   0.309    -.0845838    .0267745
       u_eng_dummy |   .0640513   .0249542     2.57   0.010      .015142    .1129606
        merchant_d |   .0253698   .0182248     1.39   0.164    -.0103501    .0610896
 dlog_high_end_cap |   .0194187   .0067558     2.87   0.004     .0061775    .0326598
  dlog_low_end_cap |   .0140216    .016539     0.85   0.397    -.0183941    .0464374
    log_firm_total |  -.0297117   .0150901    -1.97   0.049    -.0592877   -.0001357
          firm_age |  -.0056414   .0020315    -2.78   0.005     -.009623   -.0016598
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |  -.2317689   .1090228    -2.13   0.034    -.4454497   -.0180882
            18942  |  -.1436358   .0838155    -1.71   0.087    -.3079111    .0206395
            18951  |  -.2202479   .0584364    -3.77   0.000    -.3347811   -.1057146
            18952  |  -.1707528   .0757536    -2.25   0.024    -.3192272   -.0222785
            18961  |  -.2633647   .0548826    -4.80   0.000    -.3709326   -.1557967
            18962  |  -.0503435   .0843317    -0.60   0.551    -.2156306    .1149437
            18971  |  -.2351455   .0616137    -3.82   0.000    -.3559062   -.1143848
            18972  |  -.2469799   .0769269    -3.21   0.001    -.3977539   -.0962058
            18981  |  -.3053482   .0928834    -3.29   0.001    -.4873963   -.1233002
            18982  |  -.1615233   .0693215    -2.33   0.020    -.2973909   -.0256556
            18991  |  -.1003088   .0715964    -1.40   0.161    -.2406351    .0400176
            18992  |  -.2652828   .0660639    -4.02   0.000    -.3947657   -.1357999
            19001  |   -.649077    .077672    -8.36   0.000    -.8013113   -.4968427
            19002  |  -.0583173   .0707663    -0.82   0.410    -.1970167    .0803822
            19011  |  -.1169698   .0667382    -1.75   0.080    -.2477743    .0138347
            19012  |  -.0682318    .068608    -0.99   0.320     -.202701    .0662374
            19021  |  -.2446027    .058215    -4.20   0.000    -.3587019   -.1305034
            19022  |  -.1923108   .0705746    -2.72   0.006    -.3306344   -.0539871
            19031  |  -.2276858   .0638652    -3.57   0.000    -.3528592   -.1025124
            19032  |   -.496904   .1053347    -4.72   0.000    -.7033563   -.2904517
            19041  |  -.0445772   .0579341    -0.77   0.442     -.158126    .0689716
            19042  |    .148938   .1085848     1.37   0.170    -.0638843    .3617602
            19051  |  -.1532124   .0639811    -2.39   0.017     -.278613   -.0278117
            19052  |  -.1231437   .0600201    -2.05   0.040     -.240781   -.0055064
            19061  |  -.2099461    .060778    -3.45   0.001    -.3290687   -.0908234
            19062  |  -.1155281   .0599645    -1.93   0.054    -.2330563        .002
            19071  |  -.2254107    .058705    -3.84   0.000    -.3404704    -.110351
            19072  |  -.2584648   .0637141    -4.06   0.000    -.3833423   -.1335874
            19081  |  -.2585993   .0636831    -4.06   0.000    -.3834159   -.1337828
            19082  |  -.0439159   .0624821    -0.70   0.482    -.1663786    .0785468
            19091  |  -.1905091   .0605654    -3.15   0.002    -.3092151   -.0718032
            19092  |  -.1563912   .0748209    -2.09   0.037    -.3030375   -.0097449
            19101  |  -.2239604   .0658515    -3.40   0.001    -.3530269   -.0948938
            19102  |  -.1076963   .0667224    -1.61   0.107    -.2384697    .0230772
            19111  |  -.1162379   .0643589    -1.81   0.071    -.2423791    .0099033
            19112  |  -.0372259   .0697381    -0.53   0.593    -.1739101    .0994584
            19121  |  -.0635743   .0637459    -1.00   0.319    -.1885139    .0613653
            19122  |  -.1285104   .0642467    -2.00   0.045    -.2544316   -.0025892
            19131  |  -.1164261   .0652337    -1.78   0.074    -.2442819    .0114296
            19132  |  -.1193106   .0658581    -1.81   0.070    -.2483901    .0097688
                   |
             _cons |   .5028145   .1261369     3.99   0.000     .2555908    .7500383
-------------------+----------------------------------------------------------------
se                 |
num_exper_up~m_hat |   .0102924   .0026386     3.90   0.000     .0051209    .0154639
       fr_low_prod |   .0350792   .0052512     6.68   0.000     .0247869    .0453714
       u_eng_dummy |   .0210797   .0024966     8.44   0.000     .0161863     .025973
        merchant_d |    .016509   .0016832     9.81   0.000     .0132099     .019808
 dlog_high_end_cap |   .0072844   .0011647     6.25   0.000     .0050016    .0095672
  dlog_low_end_cap |   .0133666   .0041829     3.20   0.001     .0051683    .0215649
    log_firm_total |   .0081239   .0009311     8.73   0.000      .006299    .0099487
          firm_age |    .001716   .0002068     8.30   0.000     .0013107    .0021213
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |   .0734757   .0082405     8.92   0.000     .0573245    .0896269
            18942  |   .0733243   .0085833     8.54   0.000     .0565013    .0901474
            18951  |   .0715124   .0081062     8.82   0.000     .0556245    .0874004
            18952  |   .0704947   .0077577     9.09   0.000       .05529    .0856995
            18961  |   .0701267   .0076001     9.23   0.000     .0552307    .0850226
            18962  |   .0681621   .0072897     9.35   0.000     .0538746    .0824496
            18971  |   .0673713   .0068513     9.83   0.000      .053943    .0807997
            18972  |   .0670389   .0067211     9.97   0.000     .0538658    .0802119
            18981  |   .0673623   .0066486    10.13   0.000     .0543313    .0803933
            18982  |   .0661455   .0066159    10.00   0.000     .0531787    .0791124
            18991  |   .0672124   .0067014    10.03   0.000     .0540778    .0803469
            18992  |   .0670286   .0066669    10.05   0.000     .0539617    .0800955
            19001  |   .0668469    .006653    10.05   0.000     .0538072    .0798866
            19002  |   .0661103    .006645     9.95   0.000     .0530864    .0791343
            19011  |   .0662727     .00668     9.92   0.000     .0531802    .0793651
            19012  |   .0665646   .0066996     9.94   0.000     .0534337    .0796955
            19021  |   .0690088   .0068489    10.08   0.000     .0555852    .0824324
            19022  |   .0702242   .0072736     9.65   0.000     .0559683    .0844802
            19031  |    .071554   .0074895     9.55   0.000     .0568748    .0862331
            19032  |   .0710545   .0073078     9.72   0.000     .0567314    .0853776
            19041  |   .0705163   .0072858     9.68   0.000     .0562364    .0847963
            19042  |   .0703472   .0072178     9.75   0.000     .0562005    .0844939
            19051  |   .0710427   .0070847    10.03   0.000     .0571569    .0849285
            19052  |   .0703586    .006992    10.06   0.000     .0566545    .0840626
            19061  |   .0717094    .007165    10.01   0.000     .0576663    .0857525
            19062  |   .0745955   .0076286     9.78   0.000     .0596437    .0895473
            19071  |    .075216   .0077298     9.73   0.000     .0600658    .0903662
            19072  |   .0752294   .0077164     9.75   0.000     .0601055    .0903533
            19081  |   .0764528   .0079403     9.63   0.000     .0608901    .0920155
            19082  |   .0762798   .0079241     9.63   0.000     .0607489    .0918108
            19091  |   .0770842   .0083698     9.21   0.000     .0606797    .0934886
            19092  |    .077142   .0083779     9.21   0.000     .0607215    .0935624
            19101  |   .0766161   .0082852     9.25   0.000     .0603775    .0928547
            19102  |     .07771   .0085889     9.05   0.000     .0608761    .0945438
            19111  |   .0787629   .0087238     9.03   0.000     .0616646    .0958612
            19112  |   .0814798   .0092431     8.82   0.000     .0633636     .099596
            19121  |   .0807194   .0089631     9.01   0.000      .063152    .0982868
            19122  |   .0797725   .0087554     9.11   0.000     .0626123    .0969326
            19131  |   .0794702   .0085687     9.27   0.000     .0626759    .0962645
            19132  |   .0801005   .0085059     9.42   0.000     .0634293    .0967717
                   |
             _cons |   .0813876   .0078062    10.43   0.000     .0660877    .0966875
------------------------------------------------------------------------------------
r; t=505.41 19:57:12

Column (4) in Table 5

Original estimation results

sysdir set PERSONAL "/Applications/Stata/ado/personal/"
set rmsg on
bootstrap _b _se, reps(1000) seed(197406) nodots cluster(firmID) idcluster(newid) nowarn: boos_2sls_2_original
set rmsg off
r; t=0.00 21:30:10


Bootstrap results                                        Number of obs = 1,608
                                                         Replications  = 1,000

                                       (Replications based on 99 clusters in firmID)
------------------------------------------------------------------------------------
                   |   Observed   Bootstrap                         Normal-based
                   | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------------+----------------------------------------------------------------
b                  |
num_exper_up~m_hat |  -.0136359   .0087412    -1.56   0.119    -.0307683    .0034965
       fr_low_prod |  -.0804099   .0338987    -2.37   0.018    -.1468501   -.0139696
upgrade_exper_lo~t |    .081418   .0197699     4.12   0.000     .0426697    .1201663
       u_eng_dummy |   .0709999   .0253241     2.80   0.005     .0213656    .1206341
        merchant_d |   .0218151   .0189839     1.15   0.251    -.0153927    .0590229
 dlog_high_end_cap |   .0187246   .0070012     2.67   0.007     .0050024    .0324467
  dlog_low_end_cap |   .0118077   .0162206     0.73   0.467    -.0199841    .0435995
    log_firm_total |  -.0458702   .0153819    -2.98   0.003    -.0760181   -.0157222
          firm_age |  -.0089447    .002102    -4.26   0.000    -.0130645   -.0048249
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |  -.2315487   .1090091    -2.12   0.034    -.4452026   -.0178947
            18942  |  -.1509977   .0819321    -1.84   0.065    -.3115817    .0095864
            18951  |  -.2264304   .0570758    -3.97   0.000    -.3382968    -.114564
            18952  |   -.179645   .0743596    -2.42   0.016     -.325387   -.0339029
            18961  |  -.2694846   .0529201    -5.09   0.000     -.373206   -.1657632
            18962  |  -.0559701   .0835881    -0.67   0.503    -.2197999    .1078596
            18971  |  -.2358472   .0600893    -3.92   0.000    -.3536202   -.1180743
            18972  |  -.2513013   .0758327    -3.31   0.001    -.3999307   -.1026719
            18981  |  -.3068619   .0920105    -3.34   0.001    -.4871991   -.1265247
            18982  |  -.1646867   .0688441    -2.39   0.017    -.2996187   -.0297546
            18991  |   -.098971   .0701112    -1.41   0.158    -.2363863    .0384444
            18992  |  -.2624017   .0649904    -4.04   0.000    -.3897804   -.1350229
            19001  |  -.6421264   .0768054    -8.36   0.000    -.7926622   -.4915906
            19002  |  -.0607489   .0695333    -0.87   0.382    -.1970316    .0755339
            19011  |  -.1136716   .0655635    -1.73   0.083    -.2421737    .0148304
            19012  |  -.0648759   .0674915    -0.96   0.336    -.1971568     .067405
            19021  |  -.2349313   .0576239    -4.08   0.000     -.347872   -.1219905
            19022  |  -.1831559   .0707698    -2.59   0.010    -.3218621   -.0444497
            19031  |  -.2171855   .0638983    -3.40   0.001    -.3424238   -.0919472
            19032  |  -.4896982   .1049375    -4.67   0.000     -.695372   -.2840245
            19041  |  -.0418287   .0578407    -0.72   0.470    -.1551945     .071537
            19042  |   .1523369   .1080407     1.41   0.159     -.059419    .3640928
            19051  |  -.1411425   .0642063    -2.20   0.028    -.2669846   -.0153005
            19052  |  -.1094506   .0601442    -1.82   0.069    -.2273311      .00843
            19061  |  -.1917889   .0603472    -3.18   0.001    -.3100673   -.0735105
            19062  |  -.0970968   .0593456    -1.64   0.102     -.213412    .0192184
            19071  |  -.2046371   .0583906    -3.50   0.000    -.3190806   -.0901936
            19072  |  -.2377659    .063074    -3.77   0.000    -.3613886   -.1141431
            19081  |  -.2402924   .0629556    -3.82   0.000    -.3636832   -.1169016
            19082  |   -.028004   .0617743    -0.45   0.650    -.1490794    .0930714
            19091  |  -.1711682    .060882    -2.81   0.005    -.2904948   -.0518416
            19092  |   -.141601   .0736876    -1.92   0.055    -.2860262    .0028241
            19101  |  -.2078389   .0656235    -3.17   0.002    -.3364585   -.0792192
            19102  |  -.0954905   .0655307    -1.46   0.145    -.2239283    .0329473
            19111  |  -.0968287   .0646594    -1.50   0.134    -.2235588    .0299015
            19112  |  -.0166007   .0697452    -0.24   0.812    -.1532987    .1200973
            19121  |  -.0365185   .0649846    -0.56   0.574     -.163886     .090849
            19122  |   -.099508   .0660866    -1.51   0.132    -.2290354    .0300193
            19131  |  -.0824395   .0668156    -1.23   0.217    -.2133957    .0485166
            19132  |  -.0818231   .0679207    -1.20   0.228    -.2149452    .0512991
                   |
             _cons |   .6813047   .1364541     4.99   0.000     .4138596    .9487499
-------------------+----------------------------------------------------------------
se                 |
num_exper_up~m_hat |   .0123694   .0047561     2.60   0.009     .0030476    .0216911
       fr_low_prod |   .0376921   .0062059     6.07   0.000     .0255288    .0498554
upgrade_exper_lo~t |   .0223423   .0064298     3.47   0.001     .0097402    .0349444
       u_eng_dummy |   .0210835   .0025112     8.40   0.000     .0161617    .0260053
        merchant_d |   .0164733    .001711     9.63   0.000     .0131198    .0198267
 dlog_high_end_cap |   .0072584   .0011591     6.26   0.000     .0049865    .0095303
  dlog_low_end_cap |   .0133281   .0041748     3.19   0.001     .0051458    .0215105
    log_firm_total |   .0092273   .0009792     9.42   0.000      .007308    .0111465
          firm_age |   .0019348   .0002109     9.17   0.000     .0015214    .0023481
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |   .0731881   .0082139     8.91   0.000     .0570891    .0892871
            18942  |   .0730652   .0085599     8.54   0.000     .0562882    .0898422
            18951  |   .0712527   .0080819     8.82   0.000     .0554124    .0870929
            18952  |   .0702611   .0077366     9.08   0.000     .0550976    .0854246
            18961  |   .0698723   .0075797     9.22   0.000     .0550163    .0847283
            18962  |   .0679128   .0072679     9.34   0.000      .053668    .0821577
            18971  |   .0671078   .0068271     9.83   0.000     .0537271    .0804886
            18972  |   .0667869   .0067011     9.97   0.000     .0536531    .0799208
            18981  |   .0670998   .0066254    10.13   0.000     .0541142    .0800855
            18982  |   .0658923   .0065927     9.99   0.000     .0529708    .0788138
            18991  |   .0669502   .0066785    10.02   0.000     .0538607    .0800398
            18992  |   .0667709   .0066441    10.05   0.000     .0537486    .0797932
            19001  |   .0666125   .0066288    10.05   0.000     .0536203    .0796048
            19002  |   .0658549   .0066228     9.94   0.000     .0528745    .0788353
            19011  |   .0660194   .0066548     9.92   0.000     .0529761    .0790626
            19012  |   .0663104   .0066754     9.93   0.000     .0532269    .0793939
            19021  |   .0687898   .0068287    10.07   0.000     .0554057    .0821739
            19022  |   .0699944   .0072536     9.65   0.000     .0557776    .0842111
            19031  |    .071332   .0074687     9.55   0.000     .0566937    .0859704
            19032  |   .0708039   .0072865     9.72   0.000     .0565227    .0850852
            19041  |   .0702443   .0072652     9.67   0.000     .0560047    .0844839
            19042  |    .070078   .0071979     9.74   0.000     .0559704    .0841856
            19051  |    .070842   .0070632    10.03   0.000     .0569984    .0846856
            19052  |   .0701838   .0069713    10.07   0.000     .0565202    .0838473
            19061  |   .0716022   .0071458    10.02   0.000     .0575966    .0856078
            19062  |   .0744754   .0076107     9.79   0.000     .0595587    .0893922
            19071  |   .0751381   .0077052     9.75   0.000     .0600362      .09024
            19072  |   .0751498   .0076866     9.78   0.000     .0600844    .0902153
            19081  |    .076319    .007911     9.65   0.000     .0608138    .0918242
            19082  |   .0761066   .0078995     9.63   0.000     .0606238    .0915893
            19091  |   .0769656    .008351     9.22   0.000     .0605978    .0933333
            19092  |    .076947   .0083608     9.20   0.000     .0605602    .0933339
            19101  |   .0764442   .0082618     9.25   0.000     .0602515     .092637
            19102  |   .0774782   .0085649     9.05   0.000     .0606913    .0942651
            19111  |   .0786351   .0086977     9.04   0.000      .061588    .0956822
            19112  |   .0813579   .0092231     8.82   0.000     .0632809     .099435
            19121  |   .0807455   .0089422     9.03   0.000     .0632191    .0982719
            19122  |   .0798577   .0087262     9.15   0.000     .0627547    .0969607
            19131  |   .0797066   .0085406     9.33   0.000     .0629674    .0964458
            19132  |   .0804473   .0084865     9.48   0.000     .0638141    .0970805
                   |
             _cons |   .0947167   .0089509    10.58   0.000     .0771732    .1122601
------------------------------------------------------------------------------------
r; t=546.99 21:39:17

Corrected estimation results

sysdir set PERSONAL "/Applications/Stata/ado/personal/"
set rmsg on
bootstrap _b _se, reps(1000) seed(197406) nodots cluster(firmID) idcluster(newid) nowarn: boos_2sls_2_modified
set rmsg off
r; t=0.00 22:32:06


Bootstrap results                                        Number of obs = 1,608
                                                         Replications  = 1,000

                                       (Replications based on 99 clusters in firmID)
------------------------------------------------------------------------------------
                   |   Observed   Bootstrap                         Normal-based
                   | coefficient  std. err.      z    P>|z|     [95% conf. interval]
-------------------+----------------------------------------------------------------
b                  |
num_exper_up~m_hat |  -.0136359    .013527    -1.01   0.313    -.0401483    .0128765
       fr_low_prod |  -.0804099   .0352664    -2.28   0.023    -.1495306   -.0112891
upgrade_exper_lo~t |    .081418   .0340635     2.39   0.017     .0146548    .1481812
       u_eng_dummy |   .0709999   .0266415     2.67   0.008     .0187834    .1232163
        merchant_d |   .0218151    .019978     1.09   0.275    -.0173411    .0609712
 dlog_high_end_cap |   .0187246    .006934     2.70   0.007     .0051343    .0323149
  dlog_low_end_cap |   .0118077   .0160006     0.74   0.461     -.019553    .0431683
    log_firm_total |  -.0458702   .0182134    -2.52   0.012    -.0815677   -.0101726
          firm_age |  -.0089447    .002656    -3.37   0.001    -.0141504    -.003739
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |  -.2315487   .1092369    -2.12   0.034    -.4456491   -.0174483
            18942  |  -.1509977   .0820268    -1.84   0.066    -.3117673     .009772
            18951  |  -.2264304   .0577743    -3.92   0.000     -.339666   -.1131948
            18952  |   -.179645   .0744597    -2.41   0.016    -.3255834   -.0337066
            18961  |  -.2694846    .053507    -5.04   0.000    -.3743564   -.1646128
            18962  |  -.0559701   .0834335    -0.67   0.502    -.2194969    .1075566
            18971  |  -.2358472   .0603963    -3.90   0.000    -.3542218   -.1174727
            18972  |  -.2513013   .0757621    -3.32   0.001    -.3997923   -.1028103
            18981  |  -.3068619   .0924291    -3.32   0.001    -.4880197   -.1257041
            18982  |  -.1646867   .0689877    -2.39   0.017       -.2999   -.0294733
            18991  |   -.098971   .0703185    -1.41   0.159    -.2367927    .0388508
            18992  |  -.2624017   .0649865    -4.04   0.000    -.3897729   -.1350305
            19001  |  -.6421264   .0773704    -8.30   0.000    -.7937695   -.4904833
            19002  |  -.0607489    .070182    -0.87   0.387    -.1983031    .0768054
            19011  |  -.1136716   .0658935    -1.73   0.085    -.2428204    .0154771
            19012  |  -.0648759   .0679492    -0.95   0.340    -.1980539     .068302
            19021  |  -.2349313   .0580572    -4.05   0.000    -.3487213   -.1211412
            19022  |  -.1831559   .0713461    -2.57   0.010    -.3229918   -.0433201
            19031  |  -.2171855   .0642965    -3.38   0.001    -.3432044   -.0911667
            19032  |  -.4896982   .1043097    -4.69   0.000    -.6941415   -.2852549
            19041  |  -.0418287   .0582154    -0.72   0.472    -.1559288    .0722714
            19042  |   .1523369   .1076383     1.42   0.157    -.0586303    .3633041
            19051  |  -.1411425   .0644141    -2.19   0.028    -.2673918   -.0148933
            19052  |  -.1094506   .0607772    -1.80   0.072    -.2285718    .0096706
            19061  |  -.1917889   .0611768    -3.13   0.002    -.3116933   -.0718845
            19062  |  -.0970968   .0607212    -1.60   0.110    -.2161082    .0219146
            19071  |  -.2046371   .0598543    -3.42   0.001    -.3219494   -.0873249
            19072  |  -.2377659   .0646629    -3.68   0.000    -.3645028   -.1110289
            19081  |  -.2402924   .0641145    -3.75   0.000    -.3659546   -.1146302
            19082  |   -.028004   .0619641    -0.45   0.651    -.1494513    .0934434
            19091  |  -.1711682    .061139    -2.80   0.005    -.2909985   -.0513379
            19092  |   -.141601   .0745523    -1.90   0.058    -.2877209    .0045189
            19101  |  -.2078389   .0671255    -3.10   0.002    -.3394024   -.0762753
            19102  |  -.0954905   .0665397    -1.44   0.151     -.225906     .034925
            19111  |  -.0968287   .0662731    -1.46   0.144    -.2267215    .0330641
            19112  |  -.0166007   .0715186    -0.23   0.816    -.1567745    .1235732
            19121  |  -.0365185   .0670752    -0.54   0.586    -.1679834    .0949464
            19122  |   -.099508   .0671677    -1.48   0.138    -.2311543    .0321382
            19131  |  -.0824395   .0690757    -1.19   0.233    -.2178255    .0529464
            19132  |  -.0818231   .0698396    -1.17   0.241    -.2187063    .0550601
                   |
             _cons |   .6813047   .1582127     4.31   0.000     .3712135     .991396
-------------------+----------------------------------------------------------------
se                 |
num_exper_up~m_hat |   .0123694   .0063982     1.93   0.053     -.000171    .0249097
       fr_low_prod |   .0376921   .0060403     6.24   0.000     .0258534    .0495308
upgrade_exper_lo~t |   .0223423   .0092527     2.41   0.016     .0042073    .0404773
       u_eng_dummy |   .0210835   .0025002     8.43   0.000     .0161833    .0259838
        merchant_d |   .0164733   .0016729     9.85   0.000     .0131944    .0197521
 dlog_high_end_cap |   .0072584   .0011597     6.26   0.000     .0049855    .0095313
  dlog_low_end_cap |   .0133281   .0041717     3.19   0.001     .0051518    .0215045
    log_firm_total |   .0092273   .0010669     8.65   0.000     .0071362    .0113184
          firm_age |   .0019348   .0002394     8.08   0.000     .0014656    .0024039
                   |
    year_half_year |
            18932  |          0  (empty)
            18941  |   .0731881   .0081864     8.94   0.000     .0571429    .0892332
            18942  |   .0730652   .0085341     8.56   0.000     .0563386    .0897918
            18951  |   .0712527   .0080583     8.84   0.000     .0554588    .0870465
            18952  |   .0702611   .0077128     9.11   0.000     .0551443     .085378
            18961  |   .0698723   .0075546     9.25   0.000     .0550655    .0846791
            18962  |   .0679128    .007244     9.38   0.000     .0537149    .0821107
            18971  |   .0671078   .0068042     9.86   0.000      .053772    .0804437
            18972  |   .0667869   .0066798    10.00   0.000     .0536947    .0798792
            18981  |   .0670998   .0066067    10.16   0.000     .0541509    .0800488
            18982  |   .0658923   .0065766    10.02   0.000     .0530023    .0787823
            18991  |   .0669502   .0066612    10.05   0.000     .0538945    .0800059
            18992  |   .0667709   .0066267    10.08   0.000     .0537827    .0797591
            19001  |   .0666125   .0066144    10.07   0.000     .0536486    .0795765
            19002  |   .0658549   .0066065     9.97   0.000     .0529064    .0788034
            19011  |   .0660194    .006641     9.94   0.000     .0530034    .0790354
            19012  |   .0663104   .0066592     9.96   0.000     .0532586    .0793621
            19021  |   .0687898   .0068146    10.09   0.000     .0554334    .0821462
            19022  |   .0699944   .0072379     9.67   0.000     .0558084    .0841803
            19031  |    .071332    .007452     9.57   0.000     .0567264    .0859377
            19032  |   .0708039   .0072708     9.74   0.000     .0565534    .0850545
            19041  |   .0702443   .0072499     9.69   0.000     .0560347    .0844538
            19042  |    .070078   .0071817     9.76   0.000      .056002    .0841539
            19051  |    .070842   .0070477    10.05   0.000     .0570288    .0846552
            19052  |   .0701838   .0069518    10.10   0.000     .0565586     .083809
            19061  |   .0716022   .0071259    10.05   0.000     .0576358    .0855687
            19062  |   .0744754   .0075888     9.81   0.000     .0596017    .0893491
            19071  |   .0751381   .0076813     9.78   0.000      .060083    .0901932
            19072  |   .0751498   .0076653     9.80   0.000     .0601261    .0901736
            19081  |    .076319   .0078871     9.68   0.000     .0608605    .0917775
            19082  |   .0761066   .0078767     9.66   0.000     .0606684    .0915447
            19091  |   .0769656   .0083193     9.25   0.000       .06066    .0932711
            19092  |    .076947   .0083305     9.24   0.000     .0606195    .0932746
            19101  |   .0764442   .0082333     9.28   0.000     .0603073    .0925812
            19102  |   .0774782   .0085371     9.08   0.000     .0607457    .0942106
            19111  |   .0786351   .0086645     9.08   0.000      .061653    .0956172
            19112  |   .0813579    .009187     8.86   0.000     .0633517    .0993641
            19121  |   .0807455   .0089034     9.07   0.000      .063295    .0981959
            19122  |   .0798577    .008695     9.18   0.000     .0628157    .0968997
            19131  |   .0797066   .0085051     9.37   0.000     .0630369    .0963763
            19132  |   .0804473   .0084515     9.52   0.000     .0638826     .097012
                   |
             _cons |   .0947167   .0090575    10.46   0.000     .0769643    .1124691
------------------------------------------------------------------------------------
r; t=576.94 22:41:43