Question Names & Reference Numbers

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

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.

  1992: MS920323 HOME PART B  (3-5 YRS): HOW OFTEN MOTHER READS TO CHILD
  1994: MS940331 HOME PART B  (3-5 YRS): HOW OFTEN MOTHER READS TO CHILD
  1996: MS960329 HOME PART B  (3-5 YRS): HOW OFTEN MOTHER READS TO CHILD

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.

  MS981B01 HOME PART B  (3-5 YRS): HOW OFTEN MOTHER READS TO CHILD

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.

  HOME-B01 HOME (AGE 3 YRS): HOW OFTEN MOTHER READS TO CHILD
  MS1-A01 HOME (AGES 4-5 YRS): HOW OFTEN MOTHER READS TO CHILD

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:

  BKGN-12_MS1.01 CHILD BACKGROUND: HAS CHILD 01 EVER BEEN ENROLLED IN HEAD START?
  BKGN-12_MS1.02 CHILD BACKGROUND: HAS CHILD 02 EVER BEEN ENROLLED IN HEAD START?

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

  MS-BKGN-12 CHILD BACKGROUND: HAS CHILD EVER BEEN ENROLLED IN HEAD START?

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.

  1992: CS921746 CHILD BACKGROUND: HAS CHILD EVER BEEN ENROLLED IN HEAD START?
  1994: CS94-14 CHILD BACKGROUND: HAS CHILD EVER BEEN ENROLLED IN HEAD START?
  1996: CS96-14 CHILD BACKGROUND: HAS CHILD EVER BEEN ENROLLED IN HEAD START?
  1998: CS98-14 CHILD BACKGROUND: HAS CHILD EVER BEEN ENROLLED IN HEAD START?

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:

  BKGN-12 CHILD BACKGROUND: HAS CHILD EVER BEEN ENROLLED IN HEAD START?

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."

  MS-BKGN-12 CHILD BACKGROUND: HAS CHILD EVER BEEN ENROLLED IN HEAD START?
  MS1-A01 HOME (AGES 4-5 YRS): HOW  OFTEN  MOTHER  READS  TO  CHILD

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):

  CS960113 CHILD SELF-ADMIN: GONE TO MOVIES WITH PARENTS IN LAST MONTH

In 1998, item numbers are used.

  CS98001A CHILD SELF-ADMIN: GONE TO MOVIES WITH PARENTS IN LAST MONTH

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:

  CSAS001A CHILD SELF-ADMIN: GONE TO MOVIES WITH PARENTS IN LAST MONTH

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 yea) of the Family Background portion (Section 2) of the YA CAPI questionnaire:

  Q2-19 IS THIS THE FIRST TIME R STOPPED LIVING WITH MOTHER?

Questions from the Young Adult self-report booklet in 1994 and 1996 are prefixed with "YA" followed by the survey year, and then a designation of the deck and column number:

  YA940939 YA SELF-REPORT: EVER BEEN ON PROBATION?
  YA960839 YA SELF-REPORT: EVER BEEN ON PROBATION?

In 1998, question names for these self-report items no longer incorporate the deck and column numbers and are simply named according to question number sequence in the booklet:

  YA98100 YA SELF-REPORT: EVER BEEN ON PROBATION?

Starting in 2000, self-report questions appear in the self-report section of the YA CAPI questionnaire and are prefixed by "YASR":

  YASR-67 EVER BEEN ON PROBATION?

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.

  1994 RESTYPE94 TYPE OF RESIDENCE R LIVES IN - CONSTRUCTED
  1996 RESTYPE96 TYPE OF RESIDENCE R LIVES IN - CONSTRUCTED
  1998 RESTYPE98 TYPE OF RESIDENCE R LIVES IN - CONSTRUCTED
  2000 RESTYPE2000 TYPE OF RESIDENCE R LIVES IN - CONSTRUCTED
  2002 RESTYPE2002 TYPE OF RESIDENCE R LIVES IN - CONSTRUCTED
  2004 RESTYPE2004 TYPE OF RESIDENCE R LIVES IN - CONSTRUCTED
  2006 RESTYPE2006 TYPE OF RESIDENCE R LIVES IN - CONSTRUCTED
  2008 RESTYPE2008 TYPE OF RESIDENCE R LIVES IN - CONSTRUCTED

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:

  Y03840.12 IS CURRENT RESIDENCE URBAN OR RURAL?
  Y03840.13 IS CURRENT RESIDENCE IN SMSA?
  Y03565.01 REVISED YOUNG ADULT SAMPLING WEIGHT