Fielding History and Sample Issues

Fielding History and Sample Issues

Child Survey

Interview Dates. During the NLSY79 survey rounds in which multiple Child instruments were used, the child instruments were not always fielded on a single date.  For example, from 1986-2004, interviewers assigned to assess two or more children in a single family might ask the mother to complete one or more Mother Supplements (one MS for each child) on the first visit to the home. On that first visit the interviewer might complete one Child Supplement (CS) and one Child Self-Administered Supplement (CSAS), scheduling the remaining Child Supplements for all children until the next visit on a subsequent day. Even when the CSAS was folded into the Child Supplement in 2006, it was possible for a child to complete most of the CS (including the assessments) on one date, and then complete the CSAS section later. Starting in 2006, when the Mother Supplement was first integrated into the mothers' main interview, the date of the Mother supplement became the same as the mother's date of interview (DOI), since the mother's main Youth interview was generally completed in one session.

Fielding Periods. Historically, the field period of the NLSY79 Child and Young Adult data collection generally coincided with the main Youth. However, starting in 2002, main Youth and Young Adult telephone interviewing began substantially prior to the younger child interviews. While this fielding strategy had a positive impact on overall completion rates, it potentially widened the gap between the mother's interview and the assessments administered to her children later in the year. Fielding of the Child typically occurred over a period of about six months from late May through November or later. In some survey rounds a small number of cases were actually completed in the calendar year following the survey year.

As indicated in Table 1, child fielding has generally occurred over periods of approximately 6-9 months in each survey round; the young adult field period generally lasted somewhat longer. Until 2004, data collection was completed within the calendar year of the particular survey round. In 2004, child interviews were conducted June-December, with 15 cases completed in January-February 2005. In R22-2006, child interviews were conducted March-December, with 33 cases completed in January-February 2007. In R23-2008, nearly all child interviews were conducted April-December 2008, with 19 cases completed in January-February of 2009. In R24-2010, nearly all child interviews were conducted March-December 2010, with an additional two cases completed in January of 2011. In R25-2012, child interviews were conducted November 2012-August 2013, with more than half the cases completed in 2013. In R26-2014, all of the child interviews took place in 2015. R26-2014 was the last round of fielding for the Child as far as direct interviewing of the children; however, in R27-2016 mothers still completed Mother Supplements for children ages 0 to 13. In R28-2018, no Mother Supplement assessments were administered, but mothers answered a small number of child health and schooling questions for children aged 18 and younger.

Table 1. NLSY79 Child and Young Adult Surveys: Fielding Periods

Year Child fielding period Young Adult fielding period
1986 February 1986 - July 1986  
1988 June 1988 - December 1988  
1990 June 1990 - December 1990  
1992 May 1992 - December 1992  
1994 June 1994 - December 1994 June 1994 - December 1994
1996 April 1996 - November 1996 May 1996 - October 1996
1998 March 1998 - October 1998 March 1998 - September 1998
2000 May 2000 - January 2001 March 2000 - January 2001
2002 May 2002 - November 2002 January 2002 - December 2002
2004 June 2004 - February 2005 January 2004 - February 2005
2006 May 2006 - March 2007 January 2006 - March 2007
2008 April 2008 - February 2009 January 2008 - March 2009
2010 March 2010 - January 2011 December 2009 - January 2011
2012 November 2012 - August 2013 August 2012 - September 2013
2014 February 2015 - October 2015 October 2014 - October 2015
2016 N/A (last round of direct fielding of Child was 2014) October 2016 - November 2017
2018 N/A October 2018 - November 2019
2020 N/A September 2020 - December 2021


Important Information

Information on fielding (interview) dates specific to each survey round can be found in the year-specific CHILD SUPPLEMENT, CHILD SELF-ADMINISTERED SUPPLEMENT and MOTHER SUPPLEMENT areas of interest.

In 1986 and 2006-present the titles for date of interview are as follows:


In all other years these items are described with the following titles:


Changes in the Child Assessments

Over time there have been changes in the administration of various assessments in the Child surveys. Details on changes in the content, administration, or scoring of particular assessments are discussed in the appropriate assessment-specific sections of this users guide (see The Child Assessments: Introduction for an overview). Two assessments, Memory for Location and Body Parts, were administered in 1986 and 1988, but have since been deleted from the data collection effort due to funding constraints. However, the 1986 and 1988 individual items and scores for these two assessments remain in the data file and are available to users.

Not all assessments were fielded in each child survey year. In some instances, assessments were administered only to children for whom no valid score has been obtained during a previous survey. In 1988 a procedure was introduced by which children ages 10 or 11 were designated to complete any assessment for which they were age-eligible in order to establish a representative index group for future analyses. Starting in 1996, the Self-Perception Profile (What I Am Like) was only administered to children ages 12 and over. The McCarthy Verbal Memory Subscale was administered for the final time in 1994. In 2004, very young children were not administered assessments, which means that scores are not available for Motor and Social Development in 2004. In 2016, only the Mother Supplement assessments were completed (Behavior Problems Index, the HOME-SF, and Motor and Social Development). The Self-Perception Profile was administered as part of the Young Adult survey in 2016 and 2018.

Young Adult Survey

By 1994, substantial numbers of children of NLSY79 mothers had reached at least mid-adolescence. Because of the enormous potential for further research possibilities with the NLSY79 cohort and their offspring, the decision was made to separate these older children into a third NLSY79 component: the Young Adults.  Beginning in 1994, NLSY79 children ages 15 and older by the end of a survey year were no longer given cognitive and other assessments, but instead received a more standard Computer Assisted Personal Interview (CAPI) survey. This Young Adult CAPI questionnaire focuses on the transition to adulthood, with detailed questions on education, employment, training, health, fertility, parenting, family formation, attitudes, interactions with family members, substance use, sexual activity, non-normative activities, and pro-social behaviors. Many questions in the Young Adult survey parallel those asked of their mothers over the years, particularly when their mothers had been at comparable life cycle points. However, the Young Adult survey contains more in-depth data in certain areas such as sexual activity, drug use, schooling activities, attitudes, and marriage and cohabitation histories. The primary interview mode for the 1994 through 1998 survey rounds was in-person interviewing. Beginning with the 2000 survey round, the primary mode has shifted to telephone interviewing.

Older children who are defined as eligible for the Young Adult survey for a given round are said to be "fielded" in that survey year. Not all older children represented in the child file are eligible to be fielded as Young Adults, for a variety of reasons. Whereas the Child/Young Adult file includes all children known to have been born to NLSY79 mothers, the older children of mothers in the no longer interviewed military and poor white oversamples are ineligible to be interviewed as Young Adults. Additionally, children who have no child interviews or only one assessment point from very early in the child study, such as 1986 or 1988, and/or who have not been co-resident with their mothers at least part time are usually not fielded in the Young Adult sample. Generally speaking, we field older children who have either been assessed or interviewed in recent rounds, or who are currently or were typically living with their mother either full or part time during at least part of their childhood. Of course, not all of the children we field as Young Adults get interviewed. Mothers may refuse to allow younger Young Adults (under age 18) to be interviewed, the Young Adults themselves may refuse, or we may fail to locate them. 

Constraints on the Young Adult sample have changed over time as follows:

  • In 1994 and 1996, the Young Adult sample included all children who were age 15 and over by December 31 of that year and who met the other selection criteria, having been assessed or living with their mom in the two previous rounds.
  • Due to budgetary constraints, the Young Adult sample in 1998 was limited to youth through age 20 as of the interview date who met the other selection criteria.
  • With additional funding through a grant from NICHD, since 2000 the sample again included Young Adults ages 21 and older, as well as those ages 15 to 20. The selection criteria were widened to include age eligible children with at least some assessment history; therefor, children who were age-eligible but not fielded in 1994 to 1998, but had some assessment history, were fielded for the first time in 2000.
  • In 2000 only, the young adults between the ages of 15 and 20 of 38% of the black and Hispanic oversample mothers were not fielded for budgetary reasons. These Young Adults were once again eligible to be interviewed in 2002.
  • Beginning in 2010, Young Adult respondents over the age of 30 have been moved to a four-year interview cycle. The interviewed sample is selected by age as of December 31 of the survey year, so that approximately half of the older young adults are eligible each round. Beginning in 2010, young adults age 31-32, 35-36, 39-40, 43-44, etc., as of December 31 of the survey year are not fielded.
  • Beginning in 2016, the fielding age for the Young Adult was lowered so that children ages 12 and older were fielded. This ensured that we collected some of the same information from the children who would have been age-eligible for the Child Self-Administered Supplement had the Child been fielded. Children age 14 answered the same questions as those ages 15 and 16, while those ages 12 and 13 answered far fewer questions.