The Efficacy of Deliberate Practice

I am really, really trying to stay away from takedown pieces, but multiple books on the importance of practice and irrelevance of talent cite Ericsson, Krampe, and Tesch-Romer’s  “The Role of Deliberate Practice in the Acquisition of Expert Performance” (PDF) as proof of the importance of deliberate practice (and the irrelevance of innate talent, but that’s a different issue).  This study compared the best, excellent, and good violinists, and their methods of study.  They claim the most accomplished students had more accumulated hours of practice than the least, and while they all currently practiced the same amount, the most accomplished students spent more of it in deliberate practice, thus proving its importance.

Let me make this quick: the study had an n of 30, spread out over three treatment groups, all of which were recruited from a music school, and the measure of success was not “successful career” but “professor prediction of successful career”.  So if the sample size was big enough to prove anything (which it wasn’t) and the sample was representative of the population (which it wasn’t), they still only proved that professors like people who study a lot.  We’re not even getting into how they estimated cumulative lifetime hours of practice for people who started picked up an instrument at four years old.  Having this be a foundational study for multiple books is embarrassing.

My most recent encounter with this study was from The Talent Code, which cites many studies showing the best people in a field engage in deliberate practice and zero experiments showing people improved after being taught deliberate practice.  I looked on google scholar and found mostly papers on how to deliberately practice teaching, not teach deliberate practice, and a few that taught using it (without a control group).  Deliberate practice looks extremely plausible and I plan on applying more of it myself, but seriously, how has this idea been around for 20 years and no one has done the most basic experiments on it?