Exploring the validity of a test of productive vocabulary.

Abstract

Lex30 is a test of productive vocabulary which uses a word association task to elicit a lexically rich text from the learner. This text is then evaluated according to the number of infrequent words which it contains. Initial studies (Meara and Fitzpatrick, 2000) indicated that Lex30 scores might correlate with general L2 proficiency. This paper explores the reliability and validity of the test through a test-retest study and two concurrent validity measures, one using native speaker data and one using a set of collateral tests. These demonstrate that Lex30 produces reliable results and operates with a degree of validity. The results of these studies lead to suggestions as to how the Lex30 test might be improved to further increase its robustness. Lastly, we discuss ways in which the Lex30 studies have shed light on the construct of productive vocabulary and the complex nature of vocabulary knowledge.