Stakeholders and researchers in higher education have long debated the consequences of English-medium instruction (EMI); a key assumption of EMI is that student’s academic learning through English should be at least as good as learning through their first language (usually the national language). This study addressed the following question: “What is the impact from English-medium instruction on students’ academic performance in an online learning environment?” “Academic performance” was measured in two ways: number of correctly answered test questions and through-put/drop-out rate. The study adopted an experimental design involving a large group (n = 2,263) randomized control study in a programming course. Student participants were randomly allocated to an English-medium version of the course (the intervention group) or a Swedish-medium version of the course (the control group). The findings were that students enrolled on the English-medium version of the course answered statistically significantly fewer test questions correctly; the EMI students also dropped out from the course to a statistically significantly higher degree compared to students enrolled on the Swedish version of the course. The conclusion of this study is thus that EMI may, under certain circumstances, have negative consequences for students’ academic performance.

中文翻译：

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英语教学及其对学业成绩的影响：一项随机对照研究

高等教育领域的利益相关者和研究人员长期以来一直在争论英语教学（EMI）的后果。EMI 的一个关键假设是，学生通过英语进行的学术学习应该至少与通过其母语（通常是本国语言）进行的学习一样好。这项研究解决了以下问题：“在线学习环境中英语教学对学生的学业成绩有什么影响？” “学业表现”通过两种方式衡量：正确回答测试问题的数量和通过率/辍学率。该研究采用了一项涉及大群体的实验设计（n= 2,263) 编程课程中的随机对照研究。学生参与者被随机分配到英语授课版本的课程（干预组）或瑞典语授课版本的课程（对照组）。结果发现，参加英语授课课程的学生正确回答的测试问题数量明显减少；与参加瑞典语版本课程的学生相比，EMI 学生从该课程退学的程度在统计上显着更高。因此，本研究的结论是，在某些情况下，EMI 可能会对学生的学业成绩产生负面影响。