A comprehensive quality assessment of John Hattie’s Visible Learning

John Hattie’s Visible Learning aggregates over 2,400 meta-analyses into ranked effect sizes, seeking to reveal the most impactful educational practices. Despite its global influence on education, critics highlight methodological and statistical weaknesses. This study comprehensively assessed Visible Learning’s 322 influences for quality, relevance, and reproducibility. An expert panel found that 22% of the influences are highly relevant. However, only 19% meet the inclusion criteria regarding participants, intervention, comparison, and outcome alignment (PICO). Furthermore, only 2 of 301 assessed influences could be fully reproduced with respect to the reported effect size, studies, students, and effects. The assessment revealed that Visible Learning contained methodological errors that compromised both the causal interpretations and the validity of the reported effect sizes. These findings underscore significant methodological and statistical shortcomings, raising questions about the validity of Visible Learning as a basis for educational policy and practice.