The Role of Deliberate Practice in Expert Performance: Revisiting Ericsson, Krampe & Tesch-Römer (1993)
Macnamara, B. N., & Maitra, M. · 2019
grade Breplicationindependentfailed
Population
Conservatory student violinists, three skill strata (replicating the original 1993 design, n=30)
Design
Preregistered twice (OSF khjs7; results-blind Registered Report jyn5w) and DOUBLE-BLIND, unlike the original: experimenters unaware of skill group, violinists unaware there were multiple groups. N=39 Cleveland Institute of Music violinists, three faculty-nominated groups (13/13/13), sex- and age-matched. Added teacher-designed practice (Ericsson's theoretical DP) alongside practice-alone (his operational DP).
Key findings
The foundational study of deliberate-practice theory fails to replicate under double-blind, preregistered conditions. The best violinists had accumulated FEWER hours (8,224) than the merely good (9,844) — 'complete correspondence between skill level and accumulated practice' is gone. Ericsson's stricter theoretical construct (teacher-designed practice) explained no more variance than his loose operational one, removing the definitional escape hatch. Both top groups passed 10,000 h by age 20, so the number is a correlate of conservatory enrollment, not a threshold for eminence.
Genetic confound
No twin/sibling design. Retrospective self-report remains open to recall bias, though the double-blind procedure removes experimenter-expectancy inflation — likely why the effect shrank versus 1993.
Replication notes
This IS the replication: n=39 vs original n=30, preregistered and results-blind accepted at Royal Society Open Science. Direction REVERSED on the key best-vs-good comparison. No counter-replication exists.
DOI / URL
10.1098/rsos.190327
Effects
| Outcome | Metric | Value | Measure | Timing | Vs | Horizon | Class |
|---|---|---|---|---|---|---|---|
| Accumulated practice alone to age 18: best vs good violinists | mean hours; t; d | Best M=8,224 h [6,400,10,048] vs Good M=9,844 h [6,937,12,751] — best practised NUMERICALLY LESS; t24=-0.93, p=.364, d=-0.38. Core 'complete correspondence' claim NOT replicated | researcher-designed | attained expertise; retrospective; field (conservatory) | none | not-applicable | domain-skill |
| Accumulated practice alone: good vs less accomplished | mean hours; t; d | Good M=9,844 vs Less accomplished M=4,558 h [3,264,5,851]; t16.57=3.26, p=.005, d=1.33 — link survives only across the wide skill gap | researcher-designed | attained expertise; retrospective; field | none | not-applicable | domain-skill |
| Overall group effect of accumulated practice | chi-square; eta-squared | chi2(2)=13.90, p=.001, eta2=0.26 [.03,.44] — substantial but far below the original's implied r=.70, which exceeded the upper CI of the music meta-analytic r=.48 [.38,.56] | researcher-designed | attained expertise; retrospective; field | none | not-applicable | domain-skill |
| Teacher-designed practice (theoretical DP) vs practice alone | eta-squared; correlation | Teacher-designed eta2=0.23 [.02,.41] vs practice-alone eta2=0.26 — no advantage; highly correlated r37=.72, p<.001. Best M=6,251 h vs Good M=6,821 h, t24=-0.37, p=.717 | researcher-designed | attained expertise; retrospective; field | none | not-applicable | domain-skill |
| 10,000-hour benchmark | descriptive | By age 20 BOTH the best and the good violinists exceeded 10,000 h of practice alone on average — the threshold did not discriminate the top group | researcher-designed | attained expertise; field | none | not-applicable | domain-skill |
Cited by
- Deliberate practice and the 10,000-hour rulemixedconf: highgc: medium