Linking scores from two written receptive English academic vocabulary tests—The VLT-Ac and the AVT

The academic section of the Vocabulary Levels Test (VLT-Ac) and the Academic Vocabulary Test (AVT) both assess meaning-recognition knowledge of written receptive academic vocabulary, deemed central for engagement in academic activities. Depending on the purpose and context of the testing, either of the tests can be appropriate, but for research and pedagogical purposes, it is important to be able to compare scores achieved on the two tests between administrations and within similar contexts. Based on a sample of 385 upper secondary school students in university-preparatory programs (independent CEFR B2-level users of English), this study presents a comparison model by linking the VLT-Ac and the AVT using concurrent calibration procedures in Item Response Theory. The key outcome of the study is a score comparison table providing a means for approximate score comparisons. Additionally, the study showcases a viable and valid method of comparing vocabulary scores from an older test with those from a newer one.