A general framework for conducting generalizability analyses is presented. Generalizability theory is extended to situations in which the objects of measurement are not persons but other factors, such as instructional objectives, stages of learning, and treatments. (Author/PN)

A set procedure developed in this study is useful in determining sample size, based on specification of linear contrasts involving certain formula treatments. (Author/DEP)

Stability of Type I error rates and power are investigated for three forms of the Box test and two forms of the jackknife test with equal and unequal sample sizes under conditions of normality and nonnormality. The Box test is shown to be robust to violations of the assumption of normality when sampling is from leptokurtic populations. The…

This report gives some simple examples of stability for one factor and 2 x 2 factorial analysis of variance, reliability and correlations. The findings are very different: from superstability (no transformation whatsoever can change the result) to almost total instability. This is followed by a discussion of applications to multivariate analysis,…

This report describes and evaluates the major computer software packages capable of computing standard errors for statistics estimated from complex samples. It first describes the problem and the proposed solutions. The two major programs presently available, SUPER CARP and OSIRIS, are described in general terms. The kinds of statistics available…

Rules, procedures, and algorithms intended to aid researchers and practitioners in the application of generalizability theory to a broad range of measurement problems are presented. Two examples of measurement research are G studies, which examine the dependability of some general measurement procedure; and D studies, which provide the data for…

Accurate estimation of variance components used in generalizability theory is essential for the theory to be viewed as an efficacious mechanism for studying the reliability and validity of a measurement procedure. This paper explores two alternatives for dealing with the apparent instability of small sample size used in determining the accuracy of…

The purpose of this study was to empirically determine the effects of quantified violations of the underlying assumptions of parametric statistical tests commonly used in educational research, namely the correlation coefficient (r) and the t test. The effects of heterogeneity of variance, nonnormality, and nonlinear transformations of scales were…

This paper was intended to promote a deeper understanding of a statistical method called balancing developed by National Assessment of Educational Progress. Problems in estimating main effects when populations are disproportionate, balancing solutions to these problems, methods equivalent to balancing, interpretation of balanced results, and some…

Three common methodological problems in the analysis of observational data include: (1) failure to base degrees of freedom for the analysis on the appropriate sampling unit; (2) the validity of the design and data are inconsistent with the generalizations reached; (3) the statistic used to calculate coder reliability is often inappropriate and…

A broad range of strategies in sampling, measurement, design, execution, implementation, and analysis are examined. Specific strategies are suggested that tend to be successful in the real world of psychiatric clinical research. (Author)

The measurement of change is such a broad topic that this article must limit its focus to a few specific subtopics. These specific topics include: longitudinal research design, attrition in research studies, the statistical analysis of difference scores, and the comparison of analysis of variance (ANOVA) and multivariate analysis of variance…