An Investigation of IELTS and TOEFL iBT Score Compatibility.

This article investigates the compatibility of scores between the International English Language Testing System (IELTS) and the Test of English as a Foreign Language Internet-Based Test (TOEFL iBT) using data from 53 Japanese university students. It evaluates the accuracy of two existing score comparison tables: one published by Educational Testing Service (ETS, 2010) based on concurrent validity studies, and another by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT, 2018) grounded in the Common European Framework of Reference for Languages (CEFR). The study found that only about half of the participants' scores aligned with the ETS table and fewer than 30% matched the MEXT CEFR-based correspondences, with prior test-taking experience influencing score outcomes. The findings suggest that the MEXT table's score equivalencies are less reliable and that IELTS and TOEFL iBT scores should not be used interchangeably without caution, especially in Japanese university admissions contexts.