A meta-analysis of English proficiency and academic achievement in English-medium instruction

Abstract

English-medium instruction (EMI) has expanded on the assumption that students’ English proficiency underpins their academic success, yet primary evidence is strikingly inconsistent. This study reports a random-effects correlational meta-analysis of the zero-order association between English proficiency and academic achievement across 29 studies ( N = 8396) in EMI higher education in six country/context groupings, with every effect size verified against its primary report and the evidence base current to 2026. The pooled correlation was moderate and positive, r = 0.34 (95% CI [0.26, 0.42]), and robust to publication bias, study quality, and dependencies among overlapping research teams. Heterogeneity, however, was substantial ( I 2 = 88.6%), and the 95% prediction interval (−0.07 to 0.65) indicates that the true association ranges from negligible to strong across settings. Academic discipline was the only significant moderator: the correlation was moderate in mixed-discipline samples ( r = 0.38) but weak in engineering samples ( r = 0.12), though this subgroup comprised only two studies, while neither proficiency-measure type nor outcome type moderated the effect. The findings position English proficiency as a modest, context-dependent correlate of EMI success that is positive on average, and they carry a direct message for English for Academic Purposes (EAP) practice. Because proficiency at entry accounts for only a modest, uneven share of the variance in achievement, admission thresholds cannot substitute for sustained, discipline-sensitive academic-language support during study. EAP provision calibrated to the language demands of specific disciplines is likely to serve EMI students better than uniform proficiency requirements.

The authors' abstract, as published at the source. Journal of English for Academic Purposes, 2026 · DOI ↗