The present study combined a functional abilities approach to characterizing childhood disability with person-oriented analytic techniques to identify and describe functional profiles of young children with disabilities. Nationally representative data from the Pre-Elementary Education Longitudinal Study was used, which included nearly 3,000…

We conducted a potential efficacy trial examining the effects of classroom-wide implementation of the "Pyramid Model for Promoting Young Children's Social-Emotional Competence" on teachers' implementation of "Pyramid Model" practices and children's social-emotional skills and challenging behavior. Participants were 40 preschool…

Univariate procedures proposed by M. Brown and A. Forsythe (1974) and the multivariate procedures from D. Nel and C. van der Merwe (1986) were generalized to form five new multivariate alternatives to one-way multivariate analysis of variance (MANOVA) for use when dispersion matrices are heteroscedastic. These alternatives are evaluated for Type I…

Hierarchical Linear Models (HLM) have been used extensively for value-added analysis, adjusting for important student and school-level covariates such as socioeconomic status. A recently proposed alternative, the Layered Mixed Effects Model (LMEM) also analyzes learning gains, but ignores sociodemographic factors. Other features of LMEM, such as…

The Welch-James (WJ) and the Huynh Improved General Approximation (IGA) tests for interaction were examined with respect to Type I error in a between- by within-subjects repeated measures design when data were non-normal, non-spherical and heterogeneous, particularly when group sizes were unequal. The tests were computed with aligned ranks and…

Type I error rates for the Johansen test were estimated using simulated data for a variety of conditions. Results indicate that Type I error rates for the Johansen test depend heavily on the number of groups and the ratio of the smallest sample size to the number of dependent variables. Sample size guidelines are presented. (SLD)

Examines the recommendations of H. Keselman, K. Carriere, and L. Lix (1993) regarding choice of sample size for obtaining robust tests of the repeated measures main and interaction hypotheses in a one Between-Subjects by one Within- Subjects design with a Welch-James type multivariate test when covariance matrices are heterogeneous. (SLD)

A method is presented for analyzing data collected in a multiple group time-series design. This consists of testing linear hypotheses about the experimental and control group-means. Both a multivariate and a univariate procedure are described. (Author/GK)

The approximate degrees of freedom Welch-James (WJ) and Brown-Forsythe (BF) procedures for testing within-subjects effects in multivariate groups by trials repeated measures designs were investigated under departures from covariance homogeneity and normality. Empirical Type I error and power rates were obtained for least-squares estimators and…

Type I error rates for Yao's, James' first-order and second-order, and Johansen's tests of equality of mean vectors for two independent samples were estimated for various conditions defined by the degree of heteroscedasticity and nonnormality. Each procedure can be seriously nonrobust with exponential and log-normal distributions. (TJH)

Type I error rates of four multivariate tests (Pilai-Bartlett trace, Johansen's test, James' first-order test, and James' second-order test) were compared for heterogeneous covariance matrices in 360 simulated experiments. The superior performance of Johansen's test and James' second-order test is discussed. (SLD)