Study Design & Methodology
The NLTS2 design, timeline, sampling plans, data collection, instrumentation, and analysis strategies were designed by SRI International, in collaboration with a task force representing interested audiences and an advisory panel.
- Was funded by the U.S. Department of Education and documented the experiences of a national sample of students who were 13 to 16 years of age in 2000 as they moved from secondary school into adult roles. They were 21 to 25 years old at the end of the study.
- Focused on a wide range of important topics, such as high school coursework, extracurricular activities, academic performance, postsecondary education and training, employment, independent living, and community participation.
- Produced information of interest to many audiences, including state and local education agencies, the U.S. Congress, the U.S. Department of Education, parents, teachers, researchers, advocates, and policymakers.
The following design and methodology topics are covered on this page:
- Conceptual Framework
- Data Collection and Instruments
- Analyses of Potential Bias
- Links to SEELS
- Original NLTS
- National Comparisons
NLTS2 involves a large, nationally representative sample of students receiving special education who were ages 13 through 16 and in at least 7th grade on December 1, 2000. The oldest youth was 26 at the time of final data collection. Statistical summaries generated from NLTS2 generalized to students receiving special education nationally in this age group, to each of the 12 federal special education disability categories, and to each single-year age cohort. Click to view the NLTS2 Sampling Plan.
Development of the conceptual framework that guided the study was been informed by a stakeholder group representing many of the audiences that will be interested in the results of the study, including parents, general and special educators, related service personnel, researchers, and policy-makers at the federal, state, and school district levels. In addition, the design team engaged a Technical Work Group of researchers experienced in large-scale longitudinal and survey research. Click here to view the NLTS2 Conceptual Framework and Research Questions.
Information about youth with disabilities was collected repeatedly as they transitioned from secondary school to early adulthood. Given the broad range of topics that the conceptual framework encompasses, information for NLTS2 were collected from a variety of sources, including parents/guardians, teachers, principals, school records, and students themselves.
Information was collected over five waves, beginning in 2001 and ending in 2009 (the table below presents the years each instrument was fielded). Click here to view the NLTS2 Study Design, Timeline, and Data Collection.
Parent/Youth Phone Interview and/or Mail Survey
|School Characteristic Survey
|School Program Survey
*Only parent interviews collected in Wave 1
*Although student assessments were conducted over two waves, there was only one assessment per sample member
The NLTS2 design called for only one assessment per sample member. An assessment was attempted for each NLTS2 sample member for whom a telephone interview or mail questionnaire 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. This age range was selected to limit the variability in performance that could be attributed to differences in the ages of the participating youth and to mesh with the every-2-year data collection cycle of the study.
A direct assessment of youth was conducted, including measures of reading comprehension and math skills, vocabulary, science and social studies content knowledge, as well as interviews about self-concept and self-determination. The direct assessment included in the NLTS2 was selected by a workgroup of assessment and measurement experts over a 6-month period in 2000. The resulting direct assessment used research editions of subtests of the Woodcock-Johnson III (WJ III). The research editions were shorter versions of the standard WJ III assessment battery and were developed for use in NLTS2 by the original WJ III developers.
NLTS2 included a functional rating for youth with disabilities for whom the direct assessment was reported to be inappropriate because their sensory, physical, behavioral, or cognitive disabilities made them unable to follow instructions or answer questions reliably in spoken or written English, Braille, or large print. The functional rating instrument was the adult-completed Scale of Independent Behavior-Revised (SIB-R). The SIB-R is a comprehensive measure of adaptive and problem behaviors related to functional independence and adaptive functioning in school, home, employment, and community settings. Its 14 18- to 20-item subtests focus on motor skills, social interaction and communication skills, personal living skills, and community living skills. These four clusters also were combined into an overall scale referred to as "broad independence." The SIB-R has normal samples to allow comparison with the general population.
Parent/Youth Phone Interview and/or Mail Survey
Telephone interviews with parents/guardians focused on youth and family characteristics, nonschool activities, satisfaction with school programs, and activities after high school. Mail questionnaires were administered to parents who could not be reached by phone.
Youth able to answer for themselves were asked to complete a telephone interview or mail questionnaire about their experiences and outcomes.
General Education Teacher Survey
For NLTS2 study members who were reported by school staff to be enrolled in at least one general education academic class, teachers of the first such class in each student's school week were surveyed. The first academic class in the week was selected so that information would be provided on a wide range of objectively selected classes taken by youth with disabilities. General education academic teachers were asked to report background information on the class, the instructional practices used with specific individual students in the class, and ways they worked with the class as a whole. These separate reports on the instructional experiences of specific students with disabilities and of the larger classes in which they participated permitted a comparison that addressed the question of whether secondary school students with disabilities have access to the general education curriculum. Teachers also reported on the supports they received because specific individual students with disabilities were in their classes; and on their perceptions of the appropriateness of those students' placements in their classes and of students' performance in them.
School Program Survey
School staff were asked to identify the staff person most knowledgeable about the overall school programs of specific individual students. These persons, often special educators, were then asked to complete a multipurpose school program survey. One purpose was to obtain a snapshot of each student's school program in terms of the range of courses taken at the time and the setting for each of these courses. Information was also obtained on related and support services and programs provided to students, their transition planning experiences, and some aspects of their school performance (e.g., absenteeism, disciplinary actions, overall grades). In addition to this broad view of students' school programs, the survey collected information about instructional practices in both special education and vocational education classes. Respondents were asked to report on the characteristics of specific classes (e.g., size, subject) and ways teachers worked with specific individual students in the class (e.g., curriculum used, frequency of using various instructional groupings and materials, grading criteria employed). For vocational education courses taken in general education classrooms, respondents were asked to report the extent to which the kinds of classroom practices used for students with disabilities differed from those used with the class as a whole.
School Characteristic Survey
For each school attended by an NLTS2 member, a school staff person who could report on the characteristics and policies of those schools (often the principal) was surveyed to provide a school-level context for the classroom-level information collected in other surveys. Broad information about the school (e.g., grade levels served, whether public or private), as well as information about the student body (e.g., size, demographic characteristics, number of students receiving special education services, absenteeism and mobility rates), was collected. School policies that affected students with disabilities (e.g., inclusion of students with disabilities in content standards and mandated standardized testing, school promotion policies) also were addressed. For schools that serve 12th-grade students, information on rates of graduation, college entrance examination participation, and college enrollment was obtained. School-level information was linked to each NLTS2 study member enrolled at a given school.
Instruments PDFs, by Wave
TranscriptsTranscripts were collected to learn about course-taking patterns, grades, and attendance.
Response rates may affect statistical precision or sample bias. NLTS2 investigated potential bias in the sample of LEAs from which study participants were randomly selected and in the sample of Wave 1 and Wave 2 respondents. Using analyses of extant databases and a survey of a national sample of Directors of Special Education, NLTS2 reports on the Analysis of Potential Bias in the Sample of Local Education Agencies (LEAs) in the National Longitudinal Transition Study-2 (NLTS2) Sample. The implications of response rates to various NLTS2 instruments are reported in Analysis of Potential Bias in the Wave 1 and Wave 2 Respondents to the National Longitudinal Transition Study-2 (NLTS2).
The NLTS2 conceptual framework and research questions are designed to allow analyses of the relationships between NLTS2 data and data generated by OSEP's Special Education Elementary Longitudinal Study (SEELS). This 6-year study, following a group of students in special education (6 to 12 years old as of September 1, 1999), assessed the experiences and achievements of students as they transitioned from elementary to middle and middle to high school. The overlap of NLTS2 and SEELS students in high school permit linkage of the early school factors measured in SEELS with postschool experiences measured in NLTS2.
The design of NLTS2 also reflects a careful alignment with the first National Longitudinal Transition Study (NLTS), conducted by SRI International for OSEP from 1985 through 1993. By including many of the same research questions and data items that appeared in NLTS, NLTS2 provides important information about the ways in which secondary education and postschool experiences have changed for youth with disabilities in the previous decade or more.
The data collection instruments have been designed to include items that have been collected in national databases for the general youth population. This permits appropriate comparisons between NLTS2 youth and those of the same ages in the general population of youth.