Systematic review, systematic bias? An example from EMI research

Based on the rigorous systematicity assumed in systematic review methodology, it is no surprise that a prominent review such as Macaro et al.'s (2018) on English medium instruction (EMI) has been used as a basis for subsequent EMI research. However, in this article, we explore the ways in which the focus of systematic reviews can be necessarily narrowed and how this poses a risk to research when readers perceive them as offering definitive conclusions on all aspects of a subject. This article addresses two significant trends in applied linguistics. First, systematic review – that is, the use of formalised systems when reviewing literature – has become far more prominent and therefore more impactful than traditional reviews as a methodology (Chong & Plonsky, 2023). Second, there has been an explosive growth in interest in EMI research (Curle et al., 2024). There are further parallels between the two trends, given that both systematic review and EMI are umbrella terms that cover a wide range of research types. As we will see, there is perhaps more disagreement over how to conduct a systematic review than lay readers would suspect. Similarly, EMI is a broader field of research than appears in its most prominent systematic review article. Studies into EMI have explored policy, language learning, the effect on subject knowledge, attitudes towards EMI, ownership of English, and so on. Thus, while EMI is a growingly recognised field of study, it is not always clear what it means to ‘study EMI’.