What can we learn from the empirical body of literature on the association between socioeconomic status (SES) and children's word comprehension? To answer this question, a systematic review was carried out on studies in which samples of children varying in SES were directly assessed on their word comprehension abilities. The final analysis included 83 effect sizes from 40 independent samples, representing data from 8211 children between the ages of 15 and 46 months. Overall, the body of literature appeared healthy, with no significant evidence of reporting or publication biases, although studies were underpowered to detect the weighted average effect size, which was z-transformed r = 0.23 (95% CI 0.17, 0.3) over the whole included sample, and z-transformed r = 0.15 (95% CI 0.02, 0.28) at the youngest age. Exploratory analyses suggested that the correlation between SES and word comprehension strengthened with child age; and that touch-based measures led to smaller SES-word comprehension associations than both looking- and pointing-based measures. We discuss these findings to inform future empirical, theoretical, and applied research.
Scaff et al. (Sat,) studied this question.