Students with disabilities experience poorer post-school outcomes compared with their peers without disabilities. Existing experimental literature on "what works" for improving these outcomes is rare; however, a rapidly growing body of research investigates correlational relationships between experiences in school and post-school…

Educational researchers commonly use the rule of thumb of "design effect smaller than 2" as the justification of not accounting for the multilevel or clustered structure in their data. The rule, however, has not yet been systematically studied in previous research. In the present study, we generated data from three different models…

Humphreys' comments on double-median splits (TM 504 009) are essentially correct, but are not relevant to the original Kirby and Das article (EJ 182 444). His comments do not weaken our findings. (Author/RD)

Methods for ordering and selecting variables for discriminant analysis in multiple group comparison or group prediction studies include: univariate Fs, stepwise analysis, learning discriminant function (LDF) variable correlations, communalities, LDF standardized coefficients, and weighted standardized coefficients. Five indices based on distance,…

Arguments have recently been put forth that standard textbook procedures for determining the sample size necessary to achieve a certain level of power in a completely randomized design are incorrect when the dependent variable is fallible because they ignore measurement error. In fact, however, there are several correct procedures, one of which is…

A method is suggested to estimate the relationship between a latent trait and one or more manifest predictors without estimating subject parameters. The method, developed for the Rasch model, can be generalized to two-parameter and three-parameter logistic latent trait models. The model is illustrated with simulated and empirical data. (SLD)

The relative power of three possible experimental designs under the condition that data is to be analyzed by nonparametric techniques; the comparison of the power of each nonparametric technique to its parametric analogue; and the comparison of relative powers using nonparametric and parametric techniques are discussed. The three nonparametric…

A complex two-stage sample selection process was used in designing the National Longitudinal Study of the High School Class of 1972. The first-stage sampling frame used in the selection of schools was stratified by the following seven variables: public vs. private control, geographic region, grade 12 enrollment, proximity to institutions of higher…

This study found that accuracy in predicting the out-of-home placement of children with severe disabilities increased little in a large cross-sectional sample (n=5,992) over a smaller semilongitudinal sample (n=141). Factors such as age, adaptive and maladaptive behavior, and ethnicity are discussed. (Author/JDD)

An evaluation of the rules-of-thumb used to determine the minimum number of subjects required to conduct multiple regression analyses suggests that researchers who use a rule of thumb rather than power analyses trade simplicity of use for accuracy and specificity of response. Insufficient power is likely to result. (SLD)

A method for drawing inferences from complex samples is based on Rubin's approach to missing data in survey research. Standard procedures for drawing such inferences do not apply when the variables of interest are not observed directly, but must be inferred from secondary random variables which depend on the variables of interest stochastically.…

An efficiency study was conducted of the base year design used for the National Longitudinal Study of the High School Class of 1972 (NLS). Finding the optimal design involved a search for the numbers of sample schools and students that would maximize the variance at a given cost. Twenty-one variables describing students' plans, attitudes,…

An efficiency study was conducted of the sampling design used for the National Longitudinal Study of the High School Class of 1972 (NLS), and the change variables used in the first followup. Nine alternative designs were compared, using a cost model based upon the number of schools and students sampled. Fourteen change variables and eight domains…

This report is the methodology report for the National Longitudinal Study of the High School Class of 1972 follow-up in 1986. The fifth follow-up survey of the National Longitudinal Study of the High School Class of 1972 (NLS-72) took place during spring and summer of 1986. A mail questionnaire was sent to a subsample of 14,489 members of the…

Approaches to studying the relationships between stress and school organizational sources of stress were examined. Rather than sampling a number of schools and school average data indicating school health and stress levels in these schools, simple teacher samples and teacher-level analyses were used. For a sample of 1300 high school teachers in…