# Deposition of Structure Factors: CCDC Trends 2011-2016

The file CCDC-Structure_Factor_Trends-2011-2016.csv provides an indication of 
the proprtion of structures deposited at the Cambridge Crystallographic Data Centre 
(CCDC) between January 2011 and June 2016 that were accompanied by additional 
structure factor files.

The columns included are as follows:

* Period (6 monthly)
* From (start of period)
* To (end of period)
* Number of deposited structures with separate structure factor files
* Total number of structures deposited externally
* Number of deposited structures with separate structure factor files (excluding IUCr)
* Total number of structures deposited externally (excluding IUCr)
* Percentage of externally deposited structures with separate structure factor files (excluding IUCr)

"Deposited externally" means that we are only counting those structures 
submitted directly to the CCDC by researchers or through arrangements with 
publishers; the numbers do not include structures that are downloaded from 
external sources by CCDC staff and loaded internally. Figures "excluding IUCr" 
remove the impact of an exercise that was undertaken to back-populate entries 
in the Cambridge Structural Database (CSD) with structure factors originally
published alongside IUCr articles.  

The subset of depositions that are deposited externally and not associated 
with IUCr journals provides a basis for examining how often structure factors 
are deposited in separate files by depositors interacting with CCDC deposition 
services and changes in behaviour over time.

Up until June 2014 the percentage of deposits accompanied by structure factors 
in separate files (excluding IUCr) never rose above 5%. From July 2014 this 
figure rose to over 20%. A possible explanation for this is changes to the 
CCDC's deposition service made in June 2014 [1].

It should be noted that the numbers do not include depositions where only 
a single file containing both atomic coordinates and structure factors is 
provided. Figures do not therefore provide an indication of the total number 
of structures that are deposited with structure factors, just a subset where 
structure factors are provided in a separate file.

## References

[1] https://www.ccdc.cam.ac.uk/News/List/post-29/ archived at 
https://web.archive.org/web/20160629111811/https://www.ccdc.cam.ac.uk/News/List/post-29/