READ Me file 
 
# Title: National Survey on the Effects of COVID-19 on the Wellbeing of Mexican Households 
(ENCOVID-19 - MAY 2021) 
 
# Título: Encuesta Nacional sobre los Efectos del COVID-19 en el Bienestar de los Hogares 
Mexicanos (ENCOVID-19- MAYO 2021) 
 
# How to cite 
Teruel-Belismelis, Graciela; Perez-Hernandez, Victor; Gaitán-Rossi, Pablo; Vilar-Compte, 
Mireya; Hernandez-Solano, Alan; Triano-Enríquez, Manuel; López-Escobar, Emilio. (2021) 
Encuesta Nacional sobre los Efectos del COVID-19 en el Bienestar de los Hogares Mexicanos 
(ENCOVID-19 - MAYO 2021) [Data set]. EQUIDE-UIA. 
 
# ENCOVID-19 project 
Amid the COVID-19 outbreak, the ENCOVID-19 provides information on the well-being of 
Mexican households in four main domains: labor, income, mental health, and food insecurity. It 
offers timely information to understand the social consequences of the pandemic and the 
lockdown measures. It is a project consisting of a series of cross-sectional telephone surveys 
collected in key moments of the COVID-19 pandemic. In addition to the four main domains and 
a set of COVID19-related questions, the survey includes new key indicators every month to 
capture the impact of the pandemic on issues like education, social programs, and crime. This is 
the ninth dataset of the project, corresponding to May 2021, collected thirteen months after 
the lockdown began in Mexico. Data collection was performed from May 21 to Jun 17, 2021. 
 
# ENCOVID-19 project resources 
Results and additional resources regarding the project are uploaded here: 
https://equide.org/pobreza/https-equide-org-pobreza-impactos-del-covid-19-en-mexico/ 
 
# Language 
The survey was conducted in Spanish and documentation and dataset are in Spanish. 
 
#Questionnaire 
The questionnaire is available in Spanish in the file “Cuestionario Mayo 2021.pdf”. 
 
# Dataset format 
The same dataset is presented in two formats. The “.dta” dataset is fully labelled to facilitate 
the identification of variables. The “.csv” dataset eases the preservation in the repository and 
amplifies the number of statistical packages able to read it. 
 
# Methodology (text in Spanish in the file “Metodologia.pdf”) 
 
Target population: individuals 18 years or older who have a mobile phone.  
 
Sample frame: Randomly selected mobile telephone numbers taken from the publicly available 
Plan Nacional de Numeración (National Numbering Plan) from the Instituto Federal de 
Telecomunicaciones (Mexico’s Federal Institute of Telecommunications, IFT), updated just 
before the survey collection started. As of the third quarter of 2019, mobile phone coverage in 
Mexico was 96%. National surveys suggest that about 90% of all Mexican households have at 
least one mobile phone user (94% in cities and 74% in rural areas). 
 
Data Collection Technique: Telephone interviews based on a structured questionnaire using 
Computer Assisted Telephone Interviewing (CATI). Interviewers were previously trained and 
randomly supervised by the PI team to assess the quality of the interviews. Everyone worked 
from their own houses without risk of contagion.  The interview manual is included below the 
questionnaire.  
 
Sample design: One-stage probabilistic sample of mobile telephone numbers stratified at the 
state-level using Random Digit Dialing (RDD). The number selection was performed from the 
national numbering plan for each stratum using using the R package RDDQuantosIC v1.5 
(developed by Quantos). 
 
Stratification. The sample was stratified for the 32 states in Mexico. 
 
Sampling weights: To avoid minor deviations in the demographic and socioeconomic 
characteristics of our sample, simple sampling weights were estimated based on Narain (1951) 
and Horvitz-Thompson (1952). Sampling weights adjust for differences in geographic location 
(state), sex, age, and socioeconomic status’ distributions as observed in census-like data of 
2020 from INEGI (Censo de Población y Vivienda 2020). We use SES categories as defined by the 
AMAI (Mexican Market Research Association). We provide appropriate sampling weights at 
both the individual and household levels, which may be used at discretion of the user according 
to the relevant unit of analysis of each question. The suffix “_norm” indicates the normalized 
weights (i.e., such that sum to the sample size). 
 
# Institutional Review Board (IRB): The project was approved by the Ethics Committee from 
Universidad Iberoamericana with the registry: CONBIOÉTICA-09—CEI-008-2016060 
 
# Results  
Every variable is labelled in the stata data set file (.dta) according to the items in the 
questionnaire. Frequency tables with percentages for every variable are provided in the file 
“Descripcion BD.pdf”. Variable names can be linked to the questionnaire using this file.  
 
#Contact  
If international researchers require additional information, please contact Victor Perez 
(victor.hernandez@ibero.mx) or Pablo Gaitán-Rossi (pablo.gaitan@ibero.mx).
