This article describes the development and validation of the new CATSS (Computer Adaptive Test of Size and Strength), which measures vocabulary knowledge in four modalities -- productive recall, receptive recall, productive recognition, and receptive recognition. In the first part of the paper we present the assumptions that underlie the test --…

The scores from vocabulary size tests have typically been interpreted as demonstrating that the target words are "known" or "learned." But "knowing" a word should entail the ability to use it in real language communication in one or more of the four skills. It should also entail deeper knowledge, such as knowing the…