Many experimental designs in educational and behavioral research involve at least one level of clustering. Clustering affects the precision of estimators and its impact on statistics in cross-sectional studies is well known. Clustering also occurs in longitudinal designs where students that are initially grouped may be regrouped in the following…

Purpose: The purpose of this study was to document, validate, and corroborate effect size (ES) for single­-subject design in treatment of children with functional phonological disorders; to evaluate potential child-­specific contributing variables relative to ES; and to establish benchmarks for interpretation of ES for the population. Method: Data…

Prior meta-analyses have found a moderate but robust relationship between alliance and outcome across a broad spectrum of treatments, presenting concerns, contexts, and measurements. However, there continues to be a lively debate about the therapeutic role of the alliance, particularly in treatments that are tested using randomized clinical trial…

This research project is focused on theoretical and empirical works analyzing the effects of career counseling. This experimental and longitudinal study has been carried out in France; it compares a sample of individuals having undertaken competence assessment with a control group and deals with self-esteem, self-analysis, self-concept, and the…

Effective early childhood intervention and child care policies should be based on an understanding of the effects of child care quality and type on child well-being. This article describes methods for securing unbiased estimates of these effects from nonexperimental data. It focuses on longitudinal studies like the one developed by the National…

Strategies are presented for analyzing longitudinal research designs with many waves of data using hierarchical linear modeling. The approach defines well-focused parameters that yield meaningful effect size estimates and significance tests. It is illustrated with data from the Boys Town Follow-Up Study. (SLD)