The purpose of this meta-analysis was to investigate the effect of collaborative learning on student achievement. The sample of the study consisted of 20 representative studies involving 2434 participants selected from an extensive literature search based on the use of collaborative activities in a formal education setting cutting across multiple grade levels and subject domains. Analysis of representative studies (k = 28) yielded a moderately weighted average effect size of 0.26. A mixed effects model was used for the analysis of the moderators of effect size. The research design was not significant across true and quasi- designs. Two groups – high collaboration (Experimental condition) and no or less collaboration (control condition) – were compared to measure the effect of collaborative learning on the dependent variable of student achievement. The analyses of moderator variables were not significant or suffered from a lack of statistical power (i.e., grade levels). Implications for the use of the collaborative learning are discussed, and recommendations for future researchers are suggested along with the limitation and conclusions. 

Keywords: collaborative learning, meta-analysis, student achievement