This study explores the extent to which differences in research design explain variation in Head Start program impacts. We employ meta-analytic techniques to predict effect sizes for cognitive and achievement outcomes as a function of the type and rigor of research design, quality and type of outcome measure, activity level of control group, and…

We conducted a meta-analysis of 36 studies of Reading Recovery (RR), an intensive tutorial intervention designed to develop the literacy skills of low-performing first-grade students. Few individual studies of the program have yielded conclusive evidence regarding the program's effectiveness due to various methodological limitations. We relied on…

A meta analysis of preschool intervention programs is performed to arrive at an overall effect size of such programs. Results indicate that despite the diversities in intervention sites, ages of subjects, lengths of intervention, and curricula models, there is a positive homogeneous effect on the variables. (Author/LMO)