Ensuring classroom reading materials align with learners’ lexical knowledge is crucial, often requiring teachers to infer vocabulary knowledge from vocabulary test performance. However, the best approach to match learners with lexically appropriate texts based on vocabulary test scores remains unclear. This study compared two methods: vocabulary mastery level and text-range vocabulary size. A meaning-recall vocabulary levels test and a reading comprehension test were administered to 304 tertiary-level Vietnamese learners of English. Learners were alternatively grouped based on either vocabulary mastery level (no mastery, 1000-word mastery, or 2000-word mastery) or text-range size (1000, 2000, or 3000-word knowledge). Analysis revealed that the text-range vocabulary size approach provided a more accurate means of matching learners with comprehensible texts. These findings offer valuable insights for teachers and researchers in English language education, highlighting practical strategies for selecting reading materials that best support learners’ comprehension and language development.
Ha et al. (2025) studied this question.