Effects of Content and Language Integrated Learning on secondary-level students’ content learning: A meta-analysis

Abstract

Content and Language Integrated Learning (CLIL) has demonstrated benefits for target language development, specifically because the target language is used as the medium of instruction. However, existing primary studies report conflicting results regarding CLIL’s effects on knowledge acquisition of non-language content subjects. This lack of consistency in findings suggests that synthesis of CLIL study results on content subjects is necessary. To fill this gap, the present study identified 21 between-group CLIL studies on the acquisition of content knowledge among secondary school students over the past two decades, and used a multilevel meta-analysis to estimate the overall effectiveness of the CLIL approach. Based on 29 independent samples and 39 effect sizes (N = 36,905), CLIL’s general effectiveness regarding secondary-level students’ knowledge gains in content subjects was 0.09 (SE = 0.10, z = 0.85, p = .40, 95% CI [−0.11, 0.28]), indicating comparable gains of the CLIL approach with that of its mainstream counterpart. The results of the moderator analyses further confirmed the homogeneity of CLIL and mainstream groups and the nature of the content subjects as significant variables that may moderate the effectiveness of the CLIL approach.