Mexican Family Life Survey
Why I cannot download the survey data to my computer?
First, in order to access the information of the MxFLS, you need to be registered as user. Second, you have to disable the option of blocking pop-ups (sometimes, pop-ups are enabled during the process of downloading files). Specifically, the process for downloading information is the following:
1. Click on the name of the file you wish to download.
2. Fill out the information requested in the registration form.
3. Click again on the name of the file you wish to download. Immediately, a dialog box will appear where you can choose whether to open or save the file.
4. Click on your preferred option (open the file or save the file) to start downloading the data. You can download more files without having to register again.
If the process of downloading data is interrupted or you are not allowed to download the information requested, it may be due to a high number of users downloading data at that time. In this case, we kindly ask you to try again later.
Why is it that once I have downloaded the files, I cannot decompress or read these files?
To decompress the data, you need the WinZip program (version 9.0 or higher). This program can be downloaded at http://www.winzip.com/downwz.htm. Once you have decompressed the data, you need the program STATA (version 8.0 or higher) to read the files. If you do not have this program or if you have the program in a different version, you can convert the files into a different format using the StatTransfer program. This program can be downloaded at
To open the questionnaires and code manuals of the MxFLS, Adobe Acrobat is required (version 5.0 or higher). This program can be downloaded at:
What is the relationship between the information reported in the books at the household level (Book C, Book 1 and Book 2) and books at the individual level (Book 3A, Book 3B, Book 4 and Book 5)? In some cases, similar questions have different answers; which book should I focus on?
The information comprised in the books at the household level (Book C, Book 1 and Book 2) is provided by one household member, whereas the information provided in the books at the individual level (Book 3A, Book 3B, Book 4 and Book 5) is provided by each household member. For this reason, it is possible that similar questions have different answers. Each researcher should decide which book to use, depending on the purpose of the study. For more information, please consult the User Guide.
What is the difference between the information reported in Books 3A, Book 3B, Book 4 and the Book Proxy?
The Book Proxy was designed to gather information of household members who were not present at the time of the interview. Thus, the information comprised in the Book Proxy was given by another household member. For more information, please consult the User Guide.
Book C contains information on income, employment and education. This information or the number of observations is not always consistent with the information reported in the books at the individual level. What is the reason for this inconsistency?
On the one hand, the information in Book C is provided by one household member. Given that one household member provides information of other household members, it is possible that this information differs from the one provided by each household member in the books at the individual level.
On the other hand, the number of observations in Book C is not necessarily the same than the number of observations in Book 3A due to the following two reasons:
1. Non-response rates.
2. Book 3A applies only to household members 15 years old or older.
How can I obtain information on the labor income of household members?
The best way to obtain information on the labor income of household members, is to use the information on adult’s labor income, provided in Book 3A (section TB), and complement this information with the information for provided in Book 5 (section EMN) for children younger than 15 years old. Missing information can be obtained from Book C (section LS) or Book Proxy. For more information, please consult the User Guide.
Where are the weights for the data at the household and individual level?
To obtain the weights of the MxFLS-1, you need to go to the main menu, click on Data and Documentation and click on MxFLS-1. Then, you will have two options to access the data: 1) Go to Households, select Files at the Household level, Files at the Individual Level or All Files, select the Book that you are interested in, and then click on Weights to download the data into your computer. 2) Go to Weights, select Files at the Household level, Files at the Individual Level or All Files, select the Book that you are interested in, and then click on Weights to download the data into your computer. In this section, you will find a general description of the structure and use of weights. For a more detailed description on how to use weights in different types of analyses, please consult the User Guide.
To obtain the weights of the MxFLS-2, you need to go to the main menu, click on Data and Documentation and click on MxFLS-2. Then, you will have two options to access the data: 1) Go to Households, select Files at the Household level, Files at the Individual Level or All Files, select the Book that you are interested in, click on Weights Mexican Population in 2005 or Longitudinal Weights Population of 2002 to download the data into your computer. 2) Go to Weights, select Weights Mexican Population in 2005 or Longitudinal Weights Population of 2002, select Files at the Household level, Files at the Individual Level or All Files, select the Book that you are interested in, and then click on Weights to download the data into your computer. In this section, you will find a general description of the structure and use of weights. For a more detailed description on how to use weights in different types of analyses, please consult the User Guide.
How is the “Folio” that identifies each household in the survey generated?
In the MxFLS-1 and MxFLS-2, the folio is comprised of eight digits. Folios that have less than eight digits are folios that implicitly have zeros ('0') to the left (as many '0'’s as needed to complete the eight spaces). The folio is generated as follows: the first five digits correspond to a number determined by the MxFLS team to identify each household. The sixth digit identifies the type of household (Main-zero (0) or additional-from one to nine (1 to 9)). The seventh and eighth digits are always 00. The folio is a unique household identifier. There is no need to use any other variable in order to identify households between different books. For more information, please consult the User Guide.
In the MxFLS-3, the Folio or number that we use to identify households is comprised of 10 digits. The first six digits are the numbers that identify the panel household. The seventh position indicates the round in which the household was interviewed/formed for the first time. The letter “A” corresponds to panel households, interviewed/formed in 2002; letter “B” to new households, interviewed/formed in 2005 (these new households are the result of split-offs of one or more than one panel member from their original household of 2002); and “C” for new household interviewed/formed in 2009-2012. The eighth digit is either a “P” or an “H”. The letter “P” indicates that the household belongs to a panel member, whereas the letter “H” indicates that it belongs to a new member. According to fieldwork protocols, households that belong to new members are interviewed only if they are formed by the offspring (born after 2002) of a panel member. The last two digits allow to identify the new households that are formed due to split-offs of panel members from their original household of 2002. In the case of panel households, these two digits are “00”. In case of new households, the two digits correspond to the LS (individual identifier) of the panel member who splitted from the original household. If there is more than one panel member in the new household, the LS is the lower of the two. For more information regarding the generation of the folio and for cases that required special treatment, please consult the User Guide.
How should I interpret the variable ls/ls00, as an individual identifier? Does this variable have a relationship with the kinship of household members?
Section c_ls of Book C contains the variable “ls00”, which is identical to the variable “ls”. In this case, it is exactly the same to use one or the other. In Book C, section ls, a line number (variable ls) is assigned to every household member, starting with the head of household, who always has an “ls = 1”. The “ls” of other household members depends on the order in which they were interviewed. In this sense, the variable “ls” is not appropriate to identify the relationship between household members. Variables ls05, ls06 and ls07 indicate the relationship between household members. For more information, please consult the User Guide.
How is the school level registered in the education section, when the school level is expressed in semesters or trimesters?
The school level is registered in years in variables ls15_1 (Book C) and ed07_1 (Book 3A). A year equals two semesters, three quarters, four trimesters, etc.
How can I identify the type of area (urban or rural) in which a household lives?
To identify the type of area in which a household lives, it is necessary to analyze the variable “estrato” of Book C. The values in this variable are the following:
Estrato=1 Households located in localities with more than 100,000 inhabitants.
Estrato=2 Households located in localities with populations between 15,000 and 100,000.
Estrato=3 Households located in towns with a population between 2,500 and 15,000.
Estrato=4 Households located in areas with less than 2,500 inhabitants.
How can I know the date in which the household was interviewed?
The dates in which the survey was conducted are in Book C, section conpor. The variables are: day and month. However, when using this data the user has to take into account that in this section, there is NOT one observation per folio, but one per visit. The variables month is coded from 01 to 12, in which 01 corresponds to January, 02 to February, and so on.
What is the purpose of the variable “secuencia”?
The variable “secuencia” is the variable that indicates the order of events. When this variable takes the value of one (1), it refers to the event listed in the first column of the questionnaire. Value “2” refers to the second event listed, and so on. For example: in section ce1 of Book 3B, sequence = 1 corresponds to the last visit made to the respondent, while sequence = 2 refers to the second to last visit. Similar examples can be found in the User Guide.
Are the codes for municipalities (towns) and localities (villages) the same as those used by the INEGI?
The codes of state and municipality are the same than those used by the INEGI. However, due to confidentially reasons, the code for the locality does not correspond to the INEGI codes. The codes for locality are established by the MXFLS team. Additionally, to ensure confidentiality of the respondents, in some questions (like place of birth or migration), the answers regarding the municipality and locality are not public.
The survey is representative at the regional level and refers to 5 regions in the country, how do I identify these regions?
The MxFLS does not have a variable to identify the region. However, the region can be identified using the variable edo (state). The states that comprise each region are the following:
Center-Northeast Region: Entities 5, 10 and 19.
Central Region-West: Entities 11, 14 and 16.
Central Country Region: Entities 9, 15, 17, 21.
Northwest Region: Entities 3, 25, 26.
South-Southeast Region: Entities 20, 30, 31.
Is it possible to have access to a variable that identifies the Primary Sampling Units (UPM)?
No. Given the confidentiality rules that the MxFLS has to follow to comply with the security standards established prior to conducting the survey, the information regarding the respondent’s location like, municipality, city and UPM is not public.
In the MxFLS questionnaires, there are questions that are not in the databases or in the code manuals. Why is this?
There are questions that are not public due to confidentiality reasons.
Are there studies based on information from the MxFLS?
In this website, in the section of Publications you can find working papers, articles, thesis, dissertations, courses and program evaluations based on data from MxFLS. To enrich this section, we invite you to share with us studies that you or your colleagues have conducted using the MxFLS. The studies can be sent to firstname.lastname@example.org
How can I interpret the results of Books EA and EN on Cognitive Ability?
The answers to the Cognitive Ability questionnaires can be interpreted in a scale of 0 to 100. In this scale, individuals who did not have correct answers are coded with a “0”, while those who had everything correct are coded with “100”. For detailed information on the subject of individual cognitive ability, please consult the following literature:
Raven J.C., Court J.H and J. Raven (1993), Test de Matrices Progresivas. Escalas Coloreada, General y Avanzada, Paidos Iberica Eds. ISBN: 9501260607.
Is there a scale to evaluate the emotional level with information collected in the SM section (Emotional Wellbeing) of book 3B?
The questions in the Emotional Wellbeing section were taken from a mental health questionnaire designed and tested by researchers from the Mexican Institute of Psychiatry. This questionnaire is used to diagnose depressive syndrome among the Mexican population. For more details, please consult the following reference:
It is important to note that some authors who have exploited data on emotional wellbeing have used the scale of questions in a semi parametric way and with categorical variables. However, Calderon (1997) presents a different criterion that might be useful:
The questionnaire consists of 21 questions. Quantification of depressive syndrome is based on the first 20 questions only, and can be answered in the negative form (No) or the positive form, in which three possibilities are accepted (sometimes, many times, all the time). The measures are given a value of 1 for the negative answers (No), and a value of 2 to 4 for positive answers, according to a progressive order. Consequently, the scale of measurement that quantifies the depressive syndrome can take any value between 20 and 80. According to the clinical experience provided in Calderon (1997), the scale can be interpreted as follows:
20-35 = Normal person
35-45 = Person with a certain level of anxiety, which can be considered while conducting the questionnaire.
46-65 = Average depression
66-80 = Severe depression