Data Sources

Table A-1 identifies the source of data for each variable included in this report. The data that are the primary focus of the report were collected in Wave 2 (2003) through telephone interviews with youth whose parents reported they could respond to questions by phone for themselves, supplemented by mail questionnaires for youth who parents reported could answer questions for themselves but not by telephone. Self-determination skills were measured as part of an in-person interview that accompanied a direct assessment of youth's academic achievement. Parents' expectations and most individual and household characteristics were drawn from a survey of parents of NLTS2 youth, conducted by telephone and mail, in Wave 1 (2001).

Table A-1: Data sources for variables included in this report

Telephone Interviews

Wave 2 constituted the first time data were collected by telephone or mail directly from youth, and the combined youth phone interview/mail survey data set is the primary data source for this report. In addition, the Wave 1 parent interview/survey provides items related to parents' expectations and characteristics of youth.

Wave 2 youth telephone interview/mail survey. NLTS2 sample members for whom working telephone numbers and addresses were available were eligible for the Wave 2 parent/youth telephone interview in 2003. Matches of names, addresses, and telephone numbers of NLTS2 parents with existing national locator databases were conducted to maximize the completeness and accuracy of contact information and subsequent response rates. Letters were sent to parents to notify them that an interview would be attempted in the next few weeks; the letter included a toll-free telephone number for parents to call to be interviewed if they did not have a telephone number where they could be reached reliably or if they wanted to make an appointment for the interview at a specific time. Computer-assisted telephone interviewing (CATI) was used for parent and youth interviews, which were conducted between early May and mid-December 2003.

The first interview contact was made with parents of eligible sample members. Those who agreed to participate were interviewed using CATI. Items in this portion of the interview, referred to as Parent Part 1, focused on topics for which the parent was considered the most appropriate respondent (e.g., services received, family expectations). At the end of Parent Part 1, the respondent was asked the following:

My next questions are about jobs (YOUTH'S NAME) may have had, schools (he/she) may have gone to, and about (his/her) feelings about (him/herself) and (his/her) life. The questions are similar to those I've been asking you, where (he/she) will be asked to answer using scales, like "very well," "pretty well," "not very well," or "not at all well." The interview would probably last about 20 to 30 minutes. Do you think that (YOUTH'S NAME) would be able to accurately answer these kinds of questions over the telephone?

If youth could answer questions by phone, they also were told:

I also have some questions about (his/her) involvement in risk behaviors, like smoking, drinking, and sexual activity. Is it all right for me to ask (YOUTH'S NAME) questions like that?

If parents consented, interviewers asked to speak with the youth or asked for contact information to reach the youth in order to complete the youth portion of the interview, referred to as Youth Part 2.

Parents who reported that youth could not answer questions by telephone were asked:

Would (he/she) be able to accurately answer these kinds of questions using a written questionnaire?

If parents indicated youth could complete a written questionnaire, they were asked for the best address to which to send a questionnaire, and a questionnaire was sent. The questionnaire contained a subset of items from the telephone interview that were considered most important for understanding the experiences and perspectives of youth. Multiple follow-up phone or mail contacts were made to maximize the response rate for the mail survey. Data from the mail survey and Youth Part 2 of the telephone interview were merged for analysis purposes.

If parents reported that youth could not answer questions either by telephone or written questionnaire or declined to have youth asked questions related to risk behaviors, interviewers asked them to continue the interview, referred to as Parent Part 2. If youth were reported to be able to complete a telephone interview or a written questionnaire but did not after repeated attempts, parents were contacted again and asked to complete Parent Part 2 in lieu of Youth Part 2. Parent Part 2 did not include the items that are the focus of this report because they could only be answered by youth themselves.

Wave 1 parent interview/survey. The NLTS2 conceptual framework suggests that a youth's nonschool experiences, such as extracurricular activities and friendships; historical information, such as age when disability was first identified; household characteristics, such as socioeconomic status; and a family's level and type of involvement in school-related areas are related to student outcomes. Parents/guardians are the most knowledgeable about these aspects of students' lives. They also are important sources of information on outcomes across domains. Thus, parents/guardians of NLTS2 sample members were interviewed by telephone or surveyed by mail in 2001, as part of Wave 1 data collection. Interviews were conducted between mid-May and late September 2001.

All parents who could not be reached by telephone were mailed a self-administered questionnaire in a survey period that extended from September through December 2001. The questionnaire contained a subset of key items from the telephone interview.

Table A-2 reports the sample members for whom there are data from the Wave 1 parent interview and mail survey and from the Wave 2 Parent Part 1 and Parent Part 2 telephone interviews and the Youth Part 2 telephone/mail survey.

In-Person Youth Interviews

An interview was conducted with each youth for whom a direct assessment of academic abilities was completed. An assessment was attempted for each NLTS2 sample member for whom a Wave 1 telephone interview or mail questionnaire or a Wave 2 telephone interview had been completed by a parent and parental consent for the assessment had been provided. Youth were eligible for an assessment during the data collection wave in which they were 16 through 18 years old.⁵⁷ This age range was selected to limit the variability in performance that could be attributed to differences in the ages of the youth participating and to mesh with the every-2-year data collection cycle of the study. The study design linked the timing of assessments with school data collection (conducted in 2002 and 2004) because most direct assessments took place at school.

Table A-2: Response rates for NLTS2 Waves 1 and 2 parent/youth data collection

The oldest two single-year age cohorts of youth (i.e., those ages 15 or 16 when sampled) reached the eligible age range in Wave 1 (2002); 5,071 youth met the eligibility criteria for assessment at that time (see table A-3). The number of eligible youth in the younger two cohorts (those ages 13 or 14 when sampled) reached the eligible age range when Wave 2 school data were collected; 4,343 youth met the criteria in 2004. Assessment data were collected for 6,273 youth, including 3,160 who were 16 through 18 years old and eligible in Wave 1 (the 2001-02 school year) and 3,113 who were age-eligible in Wave 2 (the 2003-04 school year). Data from the two waves have been combined for the analyses included in this report; however, findings are reported from the in-person interview only for youth who also responded to either the Wave 2 youth telephone interview or mail survey.

Table A-3: Response rates for NLTS2 youth assessments

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