Investigating the Relation Between Second Language Proficiency and Study Success Using a Causal Inference Approach

Abstract Prior research suggests that second language (L2) proficiency is key in students’ study progress, but this research has mainly been carried out at universities. It is thus unclear how this relation varies across different educational levels. Moreover, previous studies are often not informative about the causality of this relation, making it difficult to base intervention policies on these studies. To address these shortcomings, we analyze a large historical registry dataset of examinees of the L2 Dutch state exam between 2011 and 2023 ( n = 12,664). First, we map out the statistical dependency between language proficiency and examinees’ study success. Next, using graphical approaches to causal inference, we estimate the effect of a hypothetical intervention: Would an increase in language proficiency affect study success rates? We replicate the relation between language proficiency and study success in university students, but it does not generalize to students in applied universities or vocational programs.