Introduction to the Created Variable Appendices

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The main file NLSY97 data set contains a number of created variables. These created variables will be included on each public release of the NLSY97. With very few exceptions, these variables are either commonly used items that are derived from a number of different NLSY97 survey questions or longitudinal items that require updating in each round. If they were not provided, creating either the longitudinal or the cross-sectional variables might present difficulties for some NLSY97 users. In general, the created variables present information in five topical areas: education, employment, family background and formation, geographic information, and income and assets.

The first five appendices present the programs that were used to create the NLSY97 variables in round 9. The majority of programs are in SAS; a few are in SPSS. In the interest of space, four variables were not included in these appendices. These are the following:

CV_INTERVIEW_CMONTH
CV_INTERVIEW_DATE
CV_AGE_INT_DATE
CV_AGE(MONTHS)_INT_DATE

These variables are either directly picked up from the data set or relatively easy to compute. In the case of CV_INTERVIEW_CMONTH and CV_AGE(MONTHS)_INT_DATE, a simple formula of {([variable year-1980]*12)+variable month} was used to translate the dates into a continuous month scheme (see Appendix 7 for a further explanation of the continuous month scheme).

The programs in this supplement are provided for the convenience of the user and are available electronically from NLS User Services (see the Table of Contents for contact information).

Appendices 6 and 7 provide detailed information about the creation of the event history variables, a special set of variables included with the main data set. Although programs are not reproduced here, the text of Appendix 6 describes the various status arrays available and discusses the creation and editing process. Appendix 7 explains the continuous month and continuous week systems used in the creation of event history variables and provides a crosswalk of continuous month/week and actual dates so that researchers can associate event history variables with other information about the respondents.

Appendices 10 and 11 describe the variables created from two special data collections: the administration of the computer-adaptive version of the Armed Services Vocational Aptitude Battery and the Transcript Survey, which gathered transcripts from high schools attended by selected NLSY97 respondents. Providing additional information about the educational experiences, abilities, and aptitudes of NLSY97 respondents, these data collections required specialized coding and variable creation procedures.

Collapsed Created Variables

To help researchers use the data more easily, survey staff have created a number of variables that combine information across all survey rounds.  These variables collapse information from the individual variable across all rounds into a single variable, regardless of interview status in the current round.  To distinguish them from other created variables, all CVC variables have reference numbers that start with "Z" rather than "R" or "S" and have question names beginning with "CVC_" instead of "CV_".  These variables will be updated each year as new information is reported. 

The variables fall into 3 main areas:

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