2011 Volume 7 Issue 1 Pages 99-119
The purpose of this paper is to review recent trends in validity and validation, particularly with regard to the argument-based approach to validity, and by using this approach, to construct a validity argument for test interpretation and use based on scores of the English Diagnostic Test of Grammar (EDiT Grammar) for Japanese learners of English. The EDiT Grammar focuses on the knowledge of basic English noun phrases, especially their internal structures. Using Chapelle, Enright, and Jamieson’s (2008a) validation framework, we first formulated the interpretive argument, and conducted two studies, one using verbal protocol analysis and the other using Rasch analysis. The results suggest that test-taking processes employed by test-takers are in accordance with the expectations drawn from the test specifications and that all the items and test-takers fit the Rasch model. These two positive results provided two strains of evidence to support inferences of evaluation and explanation, which are synthesized into the validity argument for the EDiT Grammar.
