Two commonly used test types to assess vocabulary knowledge for the purpose of reading are size and levels tests. This article first reviews several frequently stated purposes of such tests (e.g., materials selection, tracking vocabulary growth) and provides a reasoned argument for the precision needed to serve such purposes. Then three sources of…

In second language (L2) research, the lexical unit is often defined as a base word plus inflectional and derivational forms through Level 6 of Bauer and Nation's framework (WF6). WF6 use has been justified by the assumption that once a form is known, recognition of other WF6 members requires little extra effort. A more lenient view holds that an…

In response to McLean (2021), Laufer (2021) makes three claims which are either not supported by research or are based on studies with important limitations. First is that a vocabulary size, instead of a level, can be used to match learners with lexically appropriate materials despite test creators and research not supporting this. Second is that…

The last three decades have seen an increase of tests aimed at measuring an individual's vocabulary level or size. The target words used in these tests are typically sampled from word frequency lists, which are in turn based on language corpora. Conventionally, test developers sample items from frequency bands of 1000 words; different tests employ…