The meta-analyses of deliberate practice underestimate the effect size because they neglect the core characteristic of individualization—an analysis and empirical evidence

Abstract

AbstractInfluential meta-analyses have concluded that only a small to medium proportion of variance in performance can be explained by deliberate practice. We argue that the authors have neglected the most important characteristic of deliberate practice: individualization of practice. Many of the analyzed effect sizes derived from measures that did not assess individualized practice and, therefore, should not have been included in meta-analyses of deliberate practice. We present empirical evidence which suggests that the level of individualization and quality of practice (indicated by didactic educational capital) substantially influences the predictive strength of practice measures. In our study of 178 chess players, we found that at a high level of individualization and quality of practice, the effect size of structured practice was more than three times higher than that found at the average level. Our theoretical analysis, along with empirical results, support the claim that the explanatory power of deliberate practice has been considerably underestimated in the meta-analyses. The question of how important deliberate practice is for individual differences in performance remains an open question.