Despite the momentum and recent interest in this area, interaction in the context of speaking tests is a relatively young domain. Not many studies have specifically aimed at interaction in assessment. The researcher, therefore, initially incorporated as many relevant studies as possible, including dissertations, conference proceedings, and unpublished research reports. Table 1 demonstrates that the overall effect size of published studies is substantially greater (d = 1.29) than unpublished ones (d = 0.80). This difference is also statistically significant as indicated by non-overlapping confidence intervals.