Ericsson, Krampe, and Tesch-Romer’s “The Role of Deliberate Practice in the Acquisition of Expert Performance” (Psychological Review 1993) isn’t just one of the most famous articles in the history of academic psychology.  Thanks to Malcolm Gladwell’s Outliers, the article’s bullet points are now famous around the globe.  It is from this article and related research the Gladwell distills his “10,000 Hour Rule.” 

What does the 10,000 Hour Rule really say?  A few caveats aside, the Rule says that 10,000 hours of deliberate practice is both necessary and sufficient for world-class expertise.  Listen, for example, to Gladwell talk about musical expertise.

The striking thing about Ericsson’s study is that he and his colleagues
couldn’t find any “naturals,” musicians who floated effortlessly to the
top while practicing a fraction of the time their peers did. Nor could
they find any “grinds,” people who worked harder than everyone else, yet
just didn’t have what it takes to break the top ranks. Their research
suggests that once a musician has enough ability to get into a top music
school, the thing that distinguishes one performer from another is how
hard he or she works. That’s it. And what’s more, the people at the very
top don’t work just harder or even much harder than everyone else. They
work much, much harder.

This may seem like journalistic hyperbole, but it’s quite close to the original research.  Ericsson, Krampe, and Tesch-Romer:

Contrary to the popular “talent” view that asserts that differences in practice and experience cannot account for differences in expert performance, we have shown that the amount of a specific type of activity (deliberate practice) is consistently correlated with a wide range of performance including expert-level performance, when appropriate developmental differences (age) are controlled. Because of the high costs to the individuals and their environments of engaging in high levels of deliberate practice and the overlap in characteristics of deliberate practice and other known effective training situations, one can infer that high levels of deliberate practice are necessary to attain expert level performance. Our theoretical framework can also provide a sufficient account of the major facts about the nature and scarcity of exceptional performance. [emphasis mine]


We attribute the dramatic differences in performance between experts and amateurs-novices to similarly large differences in the recorded amounts of deliberate practice. Furthermore, we can account for stable individual differences in performance among individuals actively involved in deliberate practice with reference to the monotonic relation between accumulated amount of deliberate practice and current level of performance.

Although I’ve found great value in Ericsson’s research, his skepticism about innate talent always struck me as crazy.  Yes, experts energetically hone their crafts.  But everywhere I look, I see Gladwell’s “naturals” – people who are good despite relatively little time investment – and “grinds” – people who are mediocre despite massive time investment.  Only recently, though, did I discover a pile of research that confirms my big doubts about the 10,000 Hour Rule.  Highlights of the highlights:

More than 20 years ago, researchers proposed that individual differences in performance in such domains as music, sports, and games largely reflect individual differences in amount of deliberate practice, which was defined as engagement in structured activities created specifically to improve performance in a domain. This view is a frequent topic of popular science writing–but is it supported by empirical evidence? To answer this question, we conducted a meta-analysis covering all major domains in which deliberate practice has been investigated. We found that deliberate practice explained 26% of the variance in performance for games, 21% for music, 18% for sports, 4% for education, and less than 1% for professions. We conclude that deliberate practice is important, but not as important as has been argued.

The case of chess:

On average, deliberate practice explained 34% of the reliable variance in chess performance, leaving 66% unexplained and potentially explainable by other factors. We conclude that deliberate practice is not sufficient to account for individual differences in chess performance. The implication of this conclusion is that some people require much less deliberate practice than other people to reach an elite level of performance in chess. We illustrate this point in Fig. 2 using Gobet and Campitelli’s (2007) chess sample, with the 90 players classified based on their chess ratings as “master” (≥2200, n = 16), “expert” (≥2000, n = 31), or “intermediate” (<2000, n = 43). There were large differences in mean amount of deliberate practice across the skill groups: master M = 10,530 h (SD = 7414), expert M = 5673 h (SD = 4654), and intermediate M = 3179 h (SD = 4615). However, as the SDs suggest, there were very large ranges of deliberate practice within skill groups. For example, the range for the masters was 832 to 24,284 h–a difference of nearly three orders of magnitude. Furthermore, there was overlap in distributions between skill groups. For example, of the 16 masters, 31.3% (n = 5) had less deliberate practice than the mean of the expert group, one skill level down, and 12.5% (n = 2) had less deliberate practice than the mean of the intermediate group, two skill levels down. In the other direction, of the 31 intermediates, 25.8% (n = 8) had more deliberate practice than the mean of the expert group, one skill level up, and 12.9% (n = 4) had more deliberate practice than the mean of the master group, two skill levels up.

The figure:


The case of music:

On average across studies, deliberate practice explained about 30% of the reliable variance in music performance, leaving about 70% unexplained and potentially explainable by other factors. We conclude that deliberate practice is not sufficient to account for individual differences in music performance. Results of other studies provide further support for this conclusion. Simonton (1991) found a large amount of variability in the amount of time it took famous classical composers to have their first “hit,” and that the interval between the first composition and the first hit correlated significantly and negatively with maximum annual output, lifetime productivity, and posthumous reputation. Composers who rose to fame quickly-the most “talented”-had the most successful careers. Furthermore, Sloboda, Davidson, Howe, and Moore (1996) noted that although students at a selective music school (“high achievers”) had accumulated more “formal practice” than students who were learning an instrument at a non-music school (“pleasure players”), there were some individuals at each skill level (grade) who did “less than 20 per cent of the mean amount of practice for that grade” and others who did “over four times as much practice than average to attain a given grade” (p. 301).

If deliberate practice doesn’t explain everything, what does?  Lots of stuff.  Starting age.  IQ. Personality.  Specific cognitive skills, too.  Consider working memory:

Ericsson and colleagues have argued that measures of working memory capacity themselves reflect acquired skills (Ericsson & Delaney, 1999; Ericsson & Kintsch, 1995), but working memory capacity and deliberate practice correlated near zero in this study (r = .003). There was also no evidence for a Deliberate Practice × Working Memory Capacity interaction, indicating that working memory capacity was no less important a predictor of performance for pianists with thousands of hours of deliberate practice than it was for beginners. 

Fortunately, we can salvage most of the original research behind the 10,000 Hour Rule.  Instead of thinking of 10,000 hours of deliberate practice as a mandatory minimum for expertise, take it as a rule of thumb: On average, a world-class expert has to practice for about 10,000 hours to reach the top.  Instead of thinking of 10,000 hours as a guarantee of expertise, adopt a pluralistic and probabilistic approach: 10,000 hours combined with lots of innate talent will usually take you to the top. 

Most importantly, though, think of deliberate practice as a general theory of improvement, not a special theory of expertise!  Some people learn more much easily than others.  But almost anyone can improve in almost anything.  How?  By deliberately practicing the specific skills they wish to improve.  Research on deliberate practice doesn’t undermine intelligence research by showing that genius is a myth.  Instead it reinforces Transfer of Learning research by showing that learning is highly specific.

HT: GMU econ prodigy Nathaniel Bechhofer