Retention

Retention

This section provides sample sizes for the number of times younger children and young adults of different ages have been interviewed over the life course of the survey. Given that the child interviewing process began with the 1986 interview round and has to date continued on a biennial basis, the maximum number of child interviews a respondent could have to date is eight, since children age into the Young Adult survey the survey round in which they turn 15 or older and the Young Adult interviews began in 1994. Clearly, the content varies considerably between the Child and Young Adult interviews, partly because in most rounds only younger children were assessed, and partly because many of the questions are life-cycle specific. Many questions that might be relevant for an eight- or a fourteen-year old might not be appropriate for an older adolescent. Additionally, there have been some changes in questions and question wording over time, so researchers who are using these data in a longitudinal manner need to carefully review the content of the questions they are using.

The Child and Young Adult surveys are characterized by inherently different question structures, modes of data collection, and indeed potentially different research agendas. It is therefore useful to present separately the sample sizes for younger and older children, even though the ultimate research agenda in many instances may join these two sample types.

The Number of Child Interviews

Table 1 presents the number of child interviews ever completed by the NLSY79 children as of the most recent survey round. This table references age at the end of the survey year (December 31) rather than the survey date because the age determination for inclusion as a young adult rather than a younger child was the age as of the end of the calendar year. This method of computing age avoids a need to split the fourteen-year old age group between a younger child and a young adult component. Whether one uses a survey date or end-of-year age typically has little impact on the magnitude of age-specific sample sizes. Most estimates of sample size for younger child in this users guide use child age as of the survey date. This is the reason why sample sizes by age presented across tables may not always be identical.

Table 1 indicates the total number of child interviews reported for each NLSY79 child who has ever been interviewed, regardless of current age. For this table, a child is defined as interviewed if the sampling weight (CSAMWTyyyy and CSAMWT_REVyyyy) is greater than zero for a given survey year. The greatest number of possible child interviews as of the cuurent survey round would be eight biennial interviews. Only 681 of the respondents at the end of 2014 fall into that category. However, Table 1 shows much larger numbers of children in all the other interview frequencycategories. Children who fall into the older age categories as of the current round, but who have completed only a small number of interviews (e.g., 11 year olds with only one or two interview points), have missed some interviews. For example, an 11 year old in the current round could potentially have six completed interviews. The implications of repeat interviewing for these younger children are expanded on in the documentation on the child assessment data, where the extent of interview repetition is connected with the specific cognitive and socio-emotional assessments that the children complete at various ages.

Table 1. NLSY79 Children: Number of Child Interviews by Age as of December 31st, 2014

Age of Child Number of Interviews
1 2 3 4 5 6 7 8 Total
0-9 Years 0 7 2 15 15 0 0 0 39
10 Years 0 0 2 1 10 10 0 0 23
11 Years 1 0 1 1 4 25 0 0 32
12 Years 1 2 1 3 4 21 13 0 45
13 Years 2 3 4 3 4 13 51 0 80
14 Years 5 3 4 4 7 5 24 46 98
15 Years 1 5 4 5 7 16 88  0 126
16 Years 7 4 5 4 5 14 65 48 152
17 Years 5 6 11 13 13 28 132  0 208
18 Years 9 3  9 13 14 17 86 70 221
19 Years 8 15 10 14 16 36 137 0 236
20 Years 9 5 16 15 16 35 102 90 288
21 Years 12 16 16 16 19 55 199 0 333
22 Years 10 17 20 16 15 46 150 115 389
23 Years 11 11 18 15 33 94 223 0 405
24 Years 17 6 17 24 33 53 152 135 437
25 Years 15 16 14 16 43 111 306  0 521
26 Years 80 16 16 12 34 67 147 161 533
27 Years 101 14 25 19 51 114 273  0 597
28 Years 90 30 16 23 41 101 234  62 597
29 Years 28 100 16 19 41 69 380 0 653
30 Years 26 113 13 17 35 58 363 0 625
31 Years 24 123 26 32 83  343  0 0 631
32 Years 21 102 17 42 61 375  0  0 618
33 Years 32 128 23 56 352   0  0 0 591
34 Years 17 88 27 63  319  0  0 0 514
35 Years 23 84 48 273 0 0  0 0 428
36 Years 17 88 39 186 0 0 0 0 330
37-42 Years 53 188 114 388 0 0 0 0 743
Total 625 1193 534 1308 1275 1706 3125 727 10493
                   
Note: Interview status is defined as sampling weight greater than zero.