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 word's derivative forms or collocations. However, little is known about how informative various vocabulary item formats are about lexical employability or mastery of aspects of word knowledge. That is, we have little idea about what score interpretations are warranted from various item formats. This article reports on two initial studies that investigated four form-meaning item formats (multiple matching, multiple-choice, and two types of cloze) to determine how informative they can be about lexical employability and knowledge of derivatives and collocations. Results showed that the four formats performed poorly and that it may not be warranted to interpret scores from these formats as showing that vocabulary is known to the level where it can be used when reading. Furthermore, the findings suggest that scores from these tests cannot be taken to mean that the words are known to any deeper degree than just the form-meaning link.