The Web-based Open-access Reliable Decision on Synonyms (WORDS) English Vocabulary Test.

A quick and reliable test of vocabulary knowledge is a vital component of many studies looking at a range of language processing skills. Recent proliferation of online (web-based) research has generated a growing need for reliable open-access vocabulary tests that can be administered online. This data report presents the newly developed 30-item Web-based Open-access Reliable Decision on Synonyms (WORDS) English Vocabulary Test. In Experiment 1, we tested 109 participants (age range: 18-69 years) on an initial set of 51 potential multiple-choice test items in which participants read a target word (e.g., ) and selected a (near-)synonym (e.g., ) from among three semantically unrelated foils (e.g., ). We conducted an item response theory analysis of participants' accuracy data to select an optimal subset of 30 items to include in the final version of the test. In Experiment 2, we verified the reliability of this 30-item version in a different sample ( = 121; 18-79 years); reliability (internal consistency) was good (Cronbach's α = 0.82). We confirmed that, consistent with numerous previous studies, (1) responses were more accurate and quicker for more frequent compared to less frequent words, and (2) older adults showed greater vocabulary knowledge compared to younger adults. The WORDS test takes on average 4 minutes (5 minutes 40 seconds including consent/debrief) to complete. It can be freely accessed via Gorilla Open Materials (https://app.gorilla.sc/openmaterials/694887), allowing ease of use and for useful comparisons between data collected by different researchers.