Making comparisons between scores on different tests is challenging because test products differ in their design, purpose, and format (Taylor, 2004, Lim et al, 2013) and the greater the difference in design the more problematic the exercise is. Nonetheless, test score users are often interested to know how for practical purposes results on two differing tests may compare. This report summarises the findings of a small-scale empirical study intended to explore the relationship between scores on the IELTS test and scores on the Pearson Test of English Academic (PTE Academic), conducted as part of a programme of work exploring the comparability of different approaches to test design.
Correlations between scores on the individual skills were moderately good, with the notable exception of speaking. This indicates that the differences between the IELTS face-to-face Speaking test and the automated, indirect, PTE Speaking test do indeed amount to significantly divergent test constructs. Given the differences in how the Speaking and indeed the Writing sections function, recognising institutions need to consider those aspects of test coverage as well as a simple comparison of test outcomes. The Pearson test may not always be a functional equivalent for IELTS in contexts where IELTS has historically been used.