The role of deliberate practice in expert performance: revisiting Ericsson, Krampe & Tesch-Römer (1993).
Level 4 - case-series / case-control
Cross-sectional comparative study relying on retrospective recall of practice history across skill groups
PubMed 31598236 · doi:10.1098/rsos.190327
What was done
Authors attempted a direct replication of Ericsson, Krampe & Tesch-Römer's (1993) seminal study on deliberate practice across different skill levels of student violinists. Methodological adjustments to the original protocol included using a double-blind procedure, applying updated statistical analyses suited to the design, and directly comparing practice alone with teacher-designed practice.
What was found
No numerical data, sample sizes, effect sizes, or p-values are reported in the abstract. The authors reported that accumulated deliberate practice did not correspond to skill level, failing to replicate the core 1993 finding. The observed effect size was reported as substantial but considerably smaller than in the original study. Additionally, teacher-designed practice was rated as less relevant to performance improvement and explained no more variance than practice alone.
Why it matters
This replication challenges the foundational empirical basis for deliberate practice theory, indicating that practice hours explain less variance in expert performance than previously claimed.
Limits
The abstract provides no sample sizes, effect sizes, or confidence intervals. The methodology depends on retrospective recall of cumulative practice over years, which is inherently vulnerable to recall bias. Findings in student violinists may not generalize to other domains of expertise.