Article appearing in Shiken 29.2 (Dec. 2025) pp. 1-26;
Article Doi: https://doi.org/10.37546/JALTSIG.TEVAL29.2-1
By Chihiro Komiya1, James Sick2, and Stuart McLean3
1Temple University, Japan Campus
2Temple University, Japan Campus
3Kindai University
Abstract
Vocabulary knowledge can be classified as having two components, size and depth. Size refers to the number of words one recognizes at a basic degree, a quantitative aspect, whereas vocabulary depth emphasizes the richness of understanding each word, a qualitative aspect. While vocabulary size has been widely researched, less attention has been paid to depth of vocabulary knowledge. Few tests have been developed that attempt to measure the multiple components that make up depth of vocabulary knowledge, nor has validity evidence been provided for such tests, especially using Many-facet Rasch analysis. This study investigated the reliability, validity, and dimensionality of four tests targeting four components of vocabulary depth: form-meaning link, collocation, word parts, and polysemy. Data from 120 learners of English were examined using many-facet Rasch analysis. The results showed that the four tests can reasonably be combined to form a single measure labeled depth of vocabulary knowledge, with adequate reliability and validity. However, revisions on some problematic items might be necessary for greater validity.
Keywords: vocabulary depth, many-facet Rasch analysis, validity, reliability, unidimensionality