There is increasing interest in meta-analysis in different fields due to the need to combine the results of primary research. One of the crucial concepts in combining results is weighting. This study examines how Hunter and Schmidt's method, weighting by sample size; Hedges and Vevea's method, weighting by inverse variance; and Osburn and…

Most students with reading difficulties struggle to read words. We examined intervention effects for students with "significant" word reading difficulties (SWRD; standard score of 80 on at least one pretest measure of word reading), which includes individuals with or at risk for dyslexia. We investigated: (a) What are the effects of…

This Campbell systematic review examines the effects of targeted school-based interventions on standardised tests in reading and maths. The review analyses evidence from 71 studies, 52 of which are randomised controlled trials. School-based interventions targeting students with, or at risk of, academic difficulties in Grades 7-12 have on average…

In this meta-analysis, I have reviewed published and unpublished research on single-track, year-round education's effect on science and social studies achievement, 2001-2016. Of 30 studies that met inclusion criteria and had data from which an effect size estimate could be calculated, 7 reported science outcomes (18 effect size estimates) or…

This synthesis extends a report of research on extensive interventions in kindergarten through third grade (Wanzek & Vaughn, 2007) to students in Grades 4 through 12, recognizing that many of the same questions about the effectiveness of reading interventions with younger students are important to address with older students, including (a) how…

This synthesis extends a report of research on extensive interventions in kindergarten through third grade (Wanzek & Vaughn, 2007) to students in Grades 4 through 12, recognizing that many of the same questions about the effectiveness of reading interventions with younger students are important to address with older students, including (a) how…

Randomized experiments are often considered the strongest designs to study the impact of educational interventions. Perhaps the most prevalent class of designs used in large scale education experiments is the cluster randomized design in which entire schools are assigned to treatments. In cluster randomized trials (CRTs) that assign schools to…

This meta-analysis reviews experimental and quasi-experimental studies in which upper-elementary, intermediate, and secondary students with learning disabilities learned from graphic organizers. Following an exhaustive search for studies meeting specified design criteria, 55 standardized mean effect sizes were extracted from 16 articles involving…

To determine whether formative writing assessments that are directly tied to everyday classroom teaching and learning enhance students' writing performance, we conducted a meta-analysis of true and quasi-experiments conducted with students in grades 1 to 8. We found that feedback to students about writing from adults, peers, self, and computers…

Worldwide, the interest of policy-makers in participating in studies from the International Association for the Evaluation of Educational Achievement (IEA), such as Trends in International Mathematics and Science Study (TIMSS) has been growing rapidly over the past two decades. These studies offer the opportunity to relate the teaching and…

This article reports a synthesis of intervention studies conducted between 1994 and 2004 with older students (Grades 6-12) with reading difficulties. Interventions addressing decoding, fluency, vocabulary, and comprehension were included if they measured the effects on reading comprehension. Twenty-nine studies were located and synthesized.…