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…

This article develops new closed-form variance expressions for power analyses for commonly used difference-in-differences (DID) and comparative interrupted time series (CITS) panel data estimators. The main contribution is to incorporate variation in treatment timing into the analysis. The power formulas also account for other key design features…

Programs that improve teaching effectiveness represent a core strategy to improve student educational outcomes and close student achievement gaps. This article compiles empirical values of intraclass correlations for designing effective and efficient experimental studies evaluating the effects of these programs. The Early Childhood Longitudinal…

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…

Single case designs (SCDs) are short time series that assess intervention effects by measuring units repeatedly over time both in the presence and absence of treatment. For a variety of reasons, interest in the statistical analysis and meta-analysis of these designs has been growing in recent years. This paper proposes modeling SCD data with…

The aim of this study is to address and analyse pre-service teachers' mathematical reasoning skills in relation to mathematical thinking processes. For these purposes, pre-service teachers' mathematical reasoning skills namely generalising/abstraction/modelling, ratiocination, development and creative thinking skills and the relationships among…

This study provides the first longitudinally designed, classroom-based empirical test of self-determination theory's motivation mediation model. Measures of perceived autonomy support, motivation (autonomy need satisfaction), engagement, and achievement were collected from 500 (257 females, 243 males) 8th-grade students in Korea in a 3-wave…

The paper presents the first known longitudinal study of the relationship between loneliness, depressive symptoms, and suicide ideation in adolescence, in a stratified sample of high school students (Time 1 N = 1009; 57% female; Time 2 N = 541; 60% female). Cross-lagged structural equation modeling indicated that depressive symptoms led to more…

A previous Monte Carlo study examined the relative powers of several simple and more complex procedures for testing the significance of difference in mean rates of change in a controlled, longitudinal, treatment evaluation study. Results revealed that the relative powers depended on the correlation structure of the simulated repeated measurements.…

When measuring the same variables on different occasions, two procedures for canonical analysis with stationary compositing weights are developed. Both methods are extended to allow for cohort sequential designs and a numerical illustration is presented. (Author/JKS)

Since research indicates that young children influence their mothers and that mothers may exert indirect influences on their children's language learning, this correlational, longitudinal study was conducted to identify indirect routes through which early maternal speech was related to later child language development. Participants were 10…

The problem of change scores' correlation with initial status and the problem of low reliability in the measurement of change are addressed. By treating the correlation between initial status and change as a design problem rather than a statistical issue, research questions can be formulated in terms of changes in the shapes of growth curves…

Sociological and demographic research often uses variables computed as ratios. When the denominators are highly correlated, and the ratios are used in correlation or regression analysis, a statistical dependency is formed. This article investigates this problem, particularly with respect to partial correlation, multiple regression, and the…

This symposium report summarizes three studies from the Houston Parent-Child Development Center dealing with aspects of a Parent Involvement Program for low-income Mexican-American families. The studies reviewed are: (1) First Results of a Longitudinal Parent Education Program, (2) Prediction of Success in a Parent Education Program, (3)…

Education researchers have long been concerned with finding the appropriate method for correlational analysis of hierarchical data. In recent years, the alternative of hierarchical linear modeling (HLM) has come into extensive use. HLM users typically center some or all student-level predictors either at the grand mean or at the school means. This…