Meta-analysis of studies on the acquisition of receptive skills and vocabulary in CLIL

Content and language integrated learning (CLIL) is a major area of interest within the field of formal education. There are numerous studies presenting data and results of CLIL implementation. The positive impacts have been reported in building positive attitudes to language learning, to content subject learning, increasing efficacy of language learning. Questions have been raised about the factors that (may) affect research results and their interpretation. Many small studies bring statistically non-significant data as they use small convenience samples. Meta-analyses enable the researchers to synthesise data from research with the same characteristics. The present article analyses the studies that focus on CLIL implementation at primary and secondary schools with special focus on receptive skills and vocabulary gains. Out of 385 selected studies were 9 included and applying randomised-effect model evaluated. The analysis found no statistically significant differences between the CLIL and EFL groups in listening and reading performance. Concerning vocabulary the statistically significant difference in favour of CLIL (p<0,0001) with overall estimate effect 0,84 and confidence interval ranging from 0,56 to 1,11 was observed.