I. Purpose of the Study: Detecting whether interventions work or not (through main effect analysis) can provide empirical evidence regarding the causal linkage between malleable factors (e.g., interventions) and learner outcomes. In complement, moderation analyses help delineate for whom and under what conditions intervention effects are most…

With many pretreatment covariates and treatment factors, the classical factorial experiment often fails to balance covariates across multiple factorial effects simultaneously. Therefore, it is intuitive to restrict the randomization of the treatment factors to satisfy certain covariate balance criteria, possibly conforming to the tiers of…

This article examines theoretical and empirical issues related to the statistical power of impact estimates for experimental evaluations of education programs. The author considers designs where random assignment is conducted at the school, classroom, or student level, and employs a unified analytic framework using statistical methods from the…

Paired-samples experimental designs are appropriate and widely used when there is a natural correspondence or pairing of scores. However, researchers must not fail to consider the implications of undetected correlation between supposedly independent samples in the absence of explicit pairing. (SLD)

This poem, with stanzas in limerick form, refers humorously to the many threats to validity posed by problems in research design, including problems of sample selection, data collection, and data analysis. (SLD)

This bulletin for the researcher, the doctoral or master's candidate, or teacher interested in and/or conducting research is intended to (1) alert novice investigators to the major requirements and pitfalls of survey and experimental research, (2) point out the weaknesses of past business education studies, and (3) provide consumers of research…

PSYCOM is a unique mixed media package which combines high interest projects on the computer with a written text of expository material. It goes beyond most computer-assisted instruction which emphasizes drill and practice and testing of knowledge. A project might consist of a simulation or an actual experiment, or it might be a demonstration, a…

Expresses the importance of scientifically based research in education reform and explains how to judge the validity of educational research. Describes control groups, randomized and matched experiments, statistical educational significance, sample size, and the difference between scientifically based and rigorously evaluated research. (Contains…

This paper has two purposes: (1) to describe the general characteristics of a research project on which this is one part; and (2) to report an experimental attempt at improving academi c performance of low achieving ninth grade students through self concept enhancement (Experiment B). Briefly discussed are the experiments and the research design…

Along with the rapid expansion over the past decade of Head Start, a program providing comprehensive early childhood development services to low-income children, their families, and their communities, has come the demand for rigorous research to demonstrate program effectiveness. This report describes the proposed design of a national study of the…