Appendix H: Identification Codes in the Child and Young Adult Database

There are two public identification codes generated for all biological children of NLSY79 mothers, regardless of age: CPUBID and MPUBID.

CPUBID (C00001.00) is the identification code for each child in NLSY79 Child and Young Adult data. It is created by appending a 2-digit code (01 to 11) to the end of the mother’s public ID (R00001.00 in the NLSY79 data). This two-digit code generally, but not always, indicates the child’s birth order. For example, the three biological children of NLSY79 main Youth respondent with MPUBID=58 will have CPUBIDs of 5801, 5802, and 5803. CPUBID is provided for all children, regardless of age and interview status.

MPUBID (C00002.00) is the public identification code of each biological child’s mother. MPUBID can be used to link information about NLSY79 children and young adults to information about NLSY79 mothers in the main Youth database. MPUBID in the NLSY79 Child/Young Adult database corresponds to CASEID (R00001.00) in the NLSY79 main youth database. More detail can be found in this tutorial about linking NLSY79 mothers and their children.

Other Identification Variables in the Child and Young Adult Database

A Young Adult identification code, CASEID (Y00001.00), is available in the YA COMMON KEY VARIABLES area of interest. The Young Adult CASEID is only available for children who have been interviewed as young adults, whereas CPUBID is a comprehensive ID code with values for all children (including young adults), regardless of age or interview status. The YA COMMON KEY VARIABLES area of interest also contains MOTHERID (Y06508.00), which provides the mother’s public ID for all children ever interviewed as Young Adults. The YA-specific variables CASEID and MOTHERID are included for the convenience of users limiting their samples to Young Adult respondents.

A series of identification codes is included that identifies all of the siblings of each child as well as the interviewed spouse and sisters of each child's mother (if they were part of the original NLSY79 sample selected in 1979). The sibling identification codes (CSIBID01-10), the mother's spouse ID (SPOUSEID) and the mother's sisters IDs (SISTID1-SISTID4) are assigned to the CHILD BACKGROUND area of interest.

Identification codes are found in the Child Supplement, Mother Supplement, and Young Adult Instrument. To search for them in the NLS Investigator, use the Area of Interest criteria search and search under Child Background and YA Common Key Variables.