The Predictive Validity of IELTS Scores: A Meta-Analysis

Thousands of education institutions worldwide rely on IELTS scores as criteria for accepting international students whose first language is not English. Individual studies have found varying degrees of strength of correlations and conflicting results between IELTS scores and academic success. These conflicting results were examined through a meta-analysis, while also investigating multiple moderating variables: research funding bias, individual skill scores, level, field, & country of study, presence of additional English courses, and GPA timepoint. Results from 18 studies show an approaching-small effect size of r =.227 for the relationship between IELTS scores and post-secondary GPA. The majority of macro skills (listening, writing, and speaking) do not reach the small effect size, however reading approaches it with an effect size of r =.215. Most moderator analyses were inconclusive owing to the small amount of studies, but potential differences from individual studies are examined and discussed