Deliberate practice (DP) occurs when an individual intentionally repeats an
activity in order to improve performance. The claim of the DP framework is that
such behavior is necessary to achieve high levels of expert
performance. The proponents of the framework reject evidence that suggests that
other variables are also necessary to achieve high levels of expert performance,
or they claim that the relationship between those variables and expert
performance is mediated by DP. Therefore, the DP framework also implies that DP
is sufficient to achieve high levels of expert performance. We
test these claims by reviewing studies on chess expertise. We found strong
evidence that abundant DP is necessary (but not sufficient) and estimated that
the minimum requirement to achieve master level is 3,000 hours of DP. We also
review evidence showing that other factors play a role in chess skill: general
cognitive abilities, sensitive period, handedness, and season of birth.
