Examining the differential effects on taught vocabulary and generalized vocabulary outcomes in oral language interventions: a meta-analytic review

Examining the differential effects on taught vocabulary and generalized vocabulary outcomes in oral language interventions: a meta-analytic review

First Author: Kristin Rogde -- University of Oslo
Additional authors/chairs: 
Åste Mjelve Hagen; Monica Melby-Lervåg; Arne Lervåg
Keywords: vocabulary learning, Meta-analysis, Intervention studies
Abstract / Summary: 

Purpose: Meta-analyses summarizing effects from vocabulary interventions show inconsistent results. One important reason is that not all reviews separate between different types of outcomes. Whether you test an intervention effect with researcher-created tests or generalized measures can have consequences for the size of the overall effect size. We present a meta-analysis that assesses the differences between intervention effects of taught vocabulary and generalized vocabulary outcomes, and asks the following questions: 1) Are there differences in mean effect size between gains on taught vocabulary and generalized vocabulary outcomes in oral language interventions? 2) Does the amount of instruction relate differently to the size of mean effect size for the two different outcomes (taught vocabulary tests and generalized vocabulary tests)? We hypothesize that there would be a large difference in effects between taught vocabulary and generalized vocabulary outcomes and that moderators related to the amount of instruction would be stronger related to general vocabulary than to taught vocabulary. Method. Here we reviewed 17 studies based on a structured literature search (https://onlinelibrary.wiley.com/doi/full/10.1002/cl2.1059). The included studies had to report both outcomes of taught vocabulary and generalized vocabulary. Results. Results showed a large effect on taught vocabulary and no effect on generalized measures in the same studies. Conclusions. the results from this study highlight the importance of distinguishing between the interpretations of effect sizes associated with researcher created tests of taught vocabulary and generalized vocabulary outcomes.