The Effects of Repetition on Incidental Vocabulary Learning: A Meta‐Analysis of Correlational Studies

Abstract

This meta-analysis aimed to clarify the complex relationship between repetition and second language (L2) incidental vocabulary learning by meta-analyzing primary studies reporting correlation coefficients between the number of encounters and vocabulary learning. We synthesized and quantitatively analyzed 45 effect sizes from 26 studies (N = 1,918) to calculate the mean effect size of the frequency–learning relationship and to explore the extent to which 10 empirically motivated variables moderate this relationship. Results showed that there was a medium effect (r = .34) of repetition on incidental vocabulary learning. Subsequent moderator analyses revealed that variability in the size of repetition effects across studies was explained by learner variables (age, vocabulary knowledge), treatment variables (spaced learning, visual support, engagement, range in number of encounters), and methodological differences (nonword use, forewarning of