Most study samples show less variability in key variables than do their source populations due most often to indirect selection into study participation associated with a wide range of personal and circumstantial characteristics. Formulas exist to correct the distortions of population-level correlations created. Formula accuracy has been tested…

Randomized experiments are commonly used to evaluate if particular interventions improve student achievement. While these experiments can establish that a treatment actually "causes" changes, typically the participants are not randomly selected from a well-defined population and therefore the results do not readily generalize. Three…

Research was conducted to determine whether statistical sampling techniques' could be applied effectively in followup studies of high school graduates and, if so, what sampling model is most appropriate. Records at four high schools in the Santa Barbara area were examined to develop statistical, demographic profiles of two populations, the 1970…

The objectives of this project were to construct two sets of balanced repeated replication (BRR) weights for two National Education Longitudinal Study of 1988 (NELS:88) sets of weights: one based on the third follow-up survey done in 1994 (NELS88:94); and the second based on the fourth follow-up survey done in 2000 (NELS88:2000). These weights are…

A study investigated the effectiveness of a weighting procedure for adjusting survey results to correct for nonresponse bias. Using data from a Cooperative Institutional Research Program followup survey, results indicate that the procedure is highly effective in univariate distributions; its effectiveness in adjusting correlation and regression…

Survey data concerning teacher education program graduates were used to demonstrate the advantages of a stratified random sampling approach, with followup, relative to a one-shot mailing to an entire population. Sampling issues involved in such an approach are addressed, particularly with regard to quantifying the effects of nonresponse on the…

This report presents the findings of a research study, conducted by the College of the Mainland (COM) as a subcontractor for Project FOLLOW-UP, designed to test the accuracy of random sampling and to measure non-response bias in mail surveys. In 1975, a computer-generated random sample of 500 students was drawn from a population of 1,256 students…

Longitudinal measures of change are the most important kinds of estimates being produced from the National Longitudinal Study of the High School Class of 1972 (NLS). Several topics are presented in this report, most of which build on previous variance components analyses. The major areas covered are effects of stratification and clustering,…

The National Longitudinal Study of the High School Class of 1972 obtained data for 23,451 students, of whom 16,683 completed the base-year questionnaire; 21,350 completed the first follow-up; and 20,872 completed the second follow-up. This report describes the methodology for minimizing bias in the data which might be caused by nonresponse to such…

Follow-up studies are necessary for investigating the long-term, enduring, anticipated effects of bilingual education. Investigations need to be based on a recognition of their value to educational audiences, the relative merits of research issues, attention to the problem of attrition, proper selection of dependent measures, and the merits of…

The report traces the activities which led to the development of the adjusted weights--beginning with the basic National Longitudinal Study design, the base-year weight calculations, and the resurvey procedures. Next, the report describes the first follow-up weight calculations (including unadjusted student weights), nonresponse adjustment…