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Category: Project

Description: This study systematically reviews randomly selected 155 experimental studies in education field originated in the Republic of Turkey between 2010 and 2020. Indiscriminate choice of sample size in recent publications prompted us to evaluate their statistical power and precision. First, above and beyond our review, we could not identify any large-scale experiments such as cluster-randomized or multisite randomized trials, which overcome shortcomings of small-scale experiments, better suit to the organizational structure of the education field, nevertheless require far greater effort and financial resources. Second, none of the small-scale experiments has reported or conducted ex-ante power analysis. Third, results indicate that studies are sufficiently powered to detect medium to large effects (0.50 < Cohen’s d < 0.80), however they are underpowered to detect small effects (Cohen’s d ≤ 0.20). In other words, they are precise enough to detect medium effects and above (MDES ≥ .50). Finally, trends in the past ten years indicate precision remained unchanged. Findings should be interpreted in light of minimum effects in education that are relevant to education policy and practice. We emphasize the importance of conducting ex-ante power analysis, and encourage the reporting of standardized variance parameters and attrition rates to inform future studies of similar kind.