Black-White differences in an English vocabulary test using an online Prolific sample
OpenPsych , Oct. 10, 2025, ISSN: 2597-324X
We sought to examine the Black-White difference in performance on a new English vocabulary test based on 225 items. Using data from the norm sample (N = 499, Prolific) we found a gap of d = 0.74. Adjusting for test reliability, this was d = 0.75 (reliability = .977). We examined measurement invariance using Differential Item Functioning (DIF). Biased items are flagged based on p-value < .05. We found 1 biased item after Bonferroni correction for multiple comparisons. An application of Jensen’s Method of Correlated Vectors (MCV) to the item data showed a positive relationship between the Black-White difference and the items’ factor loading, with a predicted gap of d = 0.76 at loading = 1. Findings were in line with prior research of minimal bias in vocabulary tests, and a g-related difference.
