The effect of differentiated instruction approach on students’ academic achievement and attitudes: A meta-analysis study

In order to study the effect of differentiated instruction approaches on students’ academic achievement and attitudes in this meta-analysis, CoHE Thesis Center, Google Scholar, Dergi Park, Research Gate, and ERIC search engines were used to retrieve studies published in Turkey between 2010 and 2021. Out of 23 quantitative studies selected, 10 experimental and 13 quasi-experimental studies focused on students’ academic achievement and eight quantitative studies comprising three experimental and five quasi-experimental studies focused on students’ attitudes. These studies measured the pretest-posttest differences between the experimental and control groups using parametric tests such as t-test, ANOVA, and ANCOVA. The effect sizes were examined under a random-effects model, using Cohen's d and Hedges’ g indexes. According to the results, the analyses yielded a moderate effect size value of 0.791 for academic achievement and a small effect size value of 0.359 for attitude, and the overall effect size favoured the experimental group. In studies included in the analysis, the interventions lasted from 2 to 12 weeks, and the meta-regression analysis results showed that the longer the intervention duration, the more positively the academic achievement and attitude of the students are affected. However, its effect on attitude is greater than its effect on academic achievement.