Single subject (SS) designs are popular in educational and psychological research. There exist several statistical techniques designed to analyze such data and to address the question of whether an intervention has the desired impact. Recently, researchers have suggested that generalized additive models (GAMs) might be useful for modeling…

An important concern when planning research studies is to obtain maximum precision of an estimate of a treatment effect given a budget constraint. When research designs have a "multilevel" or "hierarchical" structure changes in sample size at different levels of the design will impact precision differently. Furthermore, there…

Previous work on statistical power has discussed mainly single-level designs or 2-level balanced designs with random effects. Although balanced experiments are common, in practice balance cannot always be achieved. Work on class size is one example of unbalanced designs. This study provides methods for power analysis in 2-level unbalanced designs…

Due to the clustered nature of field data, multi-level modeling has become commonly used to analyze data arising from educational field experiments. While recent methodological literature has focused on multi-level mediation analysis, relatively little attention has been devoted to mediation analysis when three levels (e.g., student, class,…

In order to explore whether or not the same theoretical model of schooling is appropriate in both private and public schools, the model from the High School and Beyond study was examined. Results indicated that the model was equally applicable in both schools. Differences between schools were discussed. (Author/GDC)

This article describes some insights of the author based on 20 years experience in using the educational research and development process. Problems and strategies related to planning, developing a prototype, and evaluating educational programs and instructional materials are discussed. (Author/JAZ)