Researchers are often interested in establishing equivalence of population variances. Traditional difference-based procedures are appropriate to answer questions about differences in some statistic (e.g., variances, etc.). However, if a researcher is interested in evaluating the equivalence of population variances, it is more appropriate to use a…

Including all children in large-scale educational studies is a pressing concern. Omitting certain types of children from studies can lead to skewed findings that promote inaccuracies about learning levels or educational quality. Increasingly, assessments are a method for investigating the quality of education systems, but national assessments are…

The uses of data on siblings for educational and psychological research purposes are explained. Examples are based on empirical data. Five types of research problems, using sibling data, are explored: (1) statistical control of family background variance in psychological or educational studies which use analysis of covariance (ANCOVA) or multiple…