Question Names & Reference Numbers

Each NLSY79 child variable has a "question name" that helps to identify it in the data file and permits users to locate the original question in the questionnaire. Variables in the NLSY79 child data are generally named according to the source from which they are derived. Items from the Child, Mother, and Child Self-Administered supplements have question names linked to the location in the instrument. For example, "CS94-14" (HAS CHILD EVER BEEN ENROLLED IN HEAD START?) comes from Q.14 asked in the first section of the Child Supplement in 1994. Acronyms are used to identify the scores derived from the child assessments administered at the time of the survey (e.g., BPI2002 for Behavior Problems Index-Raw Score, 2002). Mnemonic names identify constructed variables that are based on inputs taken from the main NLSY79 survey (e.g., AGEMOM2006 for Age of mother at interview date, 2006).

Through 1998, questions from the mother and child instruments are generally identified by "MS" for Mother Supplement or "CS" for Child Supplement and, starting in 2000, "CSAS" for the Child Self-Administered Supplement. The two digits that immediately follow this prefix refer to the year of the survey. Starting in 2000, question names for items from the child questionnaires generally indicate the topical section of the instrument from which each question was derived. For example, child question names beginning with "SCHL" come from the schooling section of the Child Supplement questionnaire; items prefixed with "HLTH" designate the child health questions in the supplement. The question name also indicates the order in which the question was administered within each section of a questionnaire. 

Constructed variables are usually named according to the topic of their content. The item called "FSTYRAFT" (C00052.00) in the CHILD BACKGROUND area of interest refers to the "first survey year of mother after the child's birth." Such items on NLSY79 mothers and their children are usually based on multiple inputs from the main youth and child survey instruments. Codebook entries for these items may include a reference to one or more main file reference number to give the user an example of the main Youth question on which the child-specific item is based. For example, in the PRE/POST NATAL CARE area of interest, the item PRE0009 (C03201.00) refers the user to R13284.00 in order to see the inputs to the variable that were extracted from the main Youth file.

• Child Question Naming Conventions
• Young Adult Question & Variable Names
• Child & Young Adult Reference Numbers

Child Question Naming Conventions

Mother Supplement Question Names

From 1986-1996 question names for items in the Mother Supplement have the following three components: (1) "MS" to designate the source of the item, (2) a 2-digit number to indicate the year of the survey round, and (3) deck and column number, used to designate the physical location on a data punch card in the days of paper data input. For example, in the item listed below, MS960329, the "MS" indicates the Mother Supplement, the "92" means the item is from the 1992 survey, and "0329" shows that the item was in Deck 3, Column 29 in the booklet.

In 1998 a similar system was used in naming Mother Supplement questions except that section number and question numbers replace the deck and column numbers, which were no longer relevant. In the example below, MS981B01 means that this item is from the Mother Supplement, 1998, Section 1-B (the HOME), question 1.

In 2000 a new naming system was introduced that more closely parallels the conventions used for the main Youth and Young Adult surveys. As seen in the example below, questions from the Mother Supplement still use the MS designation as well as a reference to the section and item number within the section, but the question names do not indicate the year of the survey.

NOTE: In 2000 the HOME and Temperament items have different question naming conventions depending on the age of the child. Items for children under age 4 that were administered in the Child Supplement are named according to the name of the assessment (e.g., HOME-B01 above). HOME and Temperament questions for children age 4 and older appear in the Mother Supplement and are therefore prefixed with "MS" followed by the section and item number (MS1-A01 means Mother Supplement, Section 1-A, question 01). Notes have been entered into the codebook for these items to alert users to this change in 2000. In 2002, all these mother-report assessment items returned to the Mother Supplement, where they continue to be administered.

Question Names for the MS in the main Youth Questionnaire. Starting in 2006, to reduce the time burden on mothers, the Mother Supplement was fully integrated into the mother's main interview as part of the Fertility Section of the Youth questionnaire. The content and basic structure of the child-based Mother Supplement were preserved, but instead of administering separate questionnaires, one for each child, interviewers asked the Mother Supplement questions in a series of child-by-child "loops" as part of the mother's main interview. The Mother Supplement data items appear both in the main Youth file and as child-based items in the MOTHER SUPPLEMENT2006-current survey areas of interest in the Child file. While the Mother Supplement question names in the mother's main Youth documentation contain the same string used for those questions in recent years, Mother Supplement items in the Child file are now all prefixed with "MS."

For example, the item on Head Start enrollment for Child 01 and Child 02 in the mother's main Youth questionnaire is documented as follows in the mother's main Youth data record:

The child-based version of this same Mother Supplement variable is labeled as follows in the Child file:

NOTE: In general, users of the Child data should access the "child-based" version of the Mother Supplement. Users of the Head Start data may be interested to know that mothers too were asked in 1994 if they attended Head Start.

Child Supplement (CS) Question Names

Through 1992, question names for items administered in the Child Supplement are constructed as follows: (1) "CS" to designate the Child Supplement, (2) a 2-digit number to indicate the year of the survey round, and (3) deck and column number, used to designate the physical location on a data punch card used in the early survey rounds. When CAPI was introduced in 1994, questions were no longer identified by deck and column but simply by item number.

Starting in 2000, questions in the Child CAPI Supplement are generally identified by the section of the questionnaire. In the example that follows, BKGN stands for the Child Background section of the questionnaire:

NOTE: Starting in 2006, nearly all the child background questions were moved into the Mother Supplement, which was integrated into the mother's main Youth interview. So an item such as BKGN-12, now appears prefixed as "MS-BKGN-12."

Child Self-Administered Supplement (CSAS) Question Names

Questions in the Child Self-Administered Supplement for children 10 and older are prefixed by "CS" until the 2000 survey when they begin with "CSAS." Through 1996, deck and column numbers were used to designate the question location in the CSAS booklet. The following example designates the year "96" and then deck "01", column "13" (pg. 3 of the paper booklet):

In 1998, item numbers are used.

Starting in 2000, the prefix CSAS designates that the item is from the Child Self-Administered Supplement and the item number corresponds to the actual question in the instrument:

Young Adult Question & Variable Names

Question names in the Young Adult surveys follow one of three general patterns. Individual items from the Young Adult CAPI questionnaire are usually prefixed by "Q" and the section number. The suffix generally indicates the order in which questions appear. Because questions asked in multiple rounds retain the same question name, many suffixes also include letters (e.g., Q4-31B). Thus, Q2-19 represents the following question (asked in each survey year) of the Family Background portion (Section 2) of the YA CAPI questionnaire:

In prior releases, questions from the Young Adult self-report booklet in 1994 and 1996 were prefixed with "YA" followed by the survey year, and then a designation of the deck and column number. In 1998, question names for these self-report items no longer incorporated the deck and column numbers and were simply named according to question number sequence in the booklet.

Since 2000, when the self-report questions were first incorporated into the self-report section of the YA CAPI questionnaire, they have been prefixed by "YASR":

In order to make the Self-Report data easier to search in Investigator, for the 2018 release, the questions from the YA Self-Report Booklets for 1994 to 1998 have been renamed to follow the naming conventions used since 2000. Any question that was in the YASRB and has remained in the CAPI questionnaire will now have the same question name across all rounds in which it was asked. Similarly, those questions only asked in the YASRB will have a CAPI-style name that allows users to easily identify these questions across the rounds in which they were asked.

Constructed variables on the Young Adult file are identified by mnemonic names related to their content. For example, the series of variables that identifies the type of residence in each survey round are named "RESTYPE" followed by a year designation.

Child & Young Adult Reference Numbers

All variables on the NLSY79 Child and Young Adult files are assigned unique identifiers called reference numbers, which determine the relative position of each variable within the codebook. Users of the main Youth data will recognize these reference numbers as conceptually equivalent to the "R"/"T" numbers used in the NLSY79 main Youth documentation.

Reference numbers that start with "C" are used for data items on the Child file. The "C" numbers appear in each NLSY79 Child codebook entry and also form the basis of the variable names on the SAS and SPSS control cards that are generated by the extraction procedures on the data set.

Reference numbers for Young Adult variables are prefixed with the letter "Y." Decimals in the Young Adult reference numbers generally indicate that more than one variable has been derived from a single question. However, decimals may also appear in reference numbers when variables have been added to the file after the original public release. For example, these variables have been added to the 1994 YA data: