Is It Really 10,000 Hours to Become an Expert?

Few ideas from psychology have travelled as far as this one: put in 10,000 hours of practice and you will become world class at almost anything. A best-selling book about success turned it into a rule in 2008, and it has been repeated in classrooms, offices and motivational posters ever since.

The rule has a real study behind it. The study just does not say what the rule says.

Where the number came from

In the early 1990s, K. Anders Ericsson, Ralf Krampe and Clemens Tesch-Römer studied violin students at the Music Academy of West Berlin. They formed three groups of ten: the best students, good students, and a less accomplished group training to become music teachers. The students kept practice diaries and estimated how much they had practised at each age since they started.

The pattern was striking. By age 18, the best violinists had accumulated around 7,410 hours of practice alone on average, the good ones around 5,301 and the future teachers around 3,420. The ranking of practice matched the ranking of skill exactly, and the authors concluded, in their 1993 paper, that differences in practice could account for much of the difference in ultimate performance.

The key idea was not hours but deliberate practice: individual training on tasks chosen to target weaknesses, with a clear goal and immediate feedback, usually designed by a teacher. That is very different from playing through pieces you already like, and it is rarely fun.

So where does 10,000 come from? It is a round number near what the top group reached a little later in their training. In their 2016 book Peak, Ericsson and the science writer Robert Pool took the popular rule apart themselves. They pointed out that there was nothing special about the figure, that only about half of the best violinists had actually reached it by age twenty, that the time needed varies enormously between fields, and that the study never showed that anyone could become an expert just by logging enough hours.

What happened when the evidence was pooled

One study of thirty violinists cannot settle a question this big. In 2014 Brooke Macnamara, David Hambrick and Frederick Oswald ran a meta-analysis across every major field in which deliberate practice had been measured.

Their headline results are worth reading slowly. Deliberate practice explained 26% of the differences in performance in games such as chess, 21% in music, 18% in sports, 4% in education and less than 1% in professions.

In plain terms: if you knew exactly how much two chess players had practised, you would be able to predict about a quarter of the gap between them. The other three quarters depend on something else. The authors' conclusion was balanced: deliberate practice is important, but not as important as had been argued.

A follow-up focused on sport found that practice explained 18% of the differences in performance overall but only about 1% among elite athletes. Once everyone at the top has trained enormously, more hours no longer separate them much. The same analysis found that the most skilled athletes had not started their sport earlier in childhood than less skilled ones.

The replication

In 2019 Macnamara and Megha Maitra went back to the original design with a new sample of violin students, this time with a double-blind procedure and statistics better suited to the data. They did not reproduce the core finding that accumulated practice lined up with each skill level. Practice still mattered - the effect was substantial - but it was considerably smaller than the effect the original study had reported.

Where the debate stands

Ericsson did not accept these conclusions. In a published reply he argued that the sports meta-analysis had counted almost any activity as practice, including group sessions, watching games and even play, whereas his theory was about a specific, teacher-guided kind of training. Summing every hour as if all hours were equal, he wrote, was bound to underestimate the effect of the right kind of practice. Macnamara and her colleagues replied in turn, and the disagreement has not been fully resolved.

There is a fair point on each side. Most studies rely on people remembering, years later, how much they practised, and noisy memories make any effect look smaller than it is. On the other hand, if deliberate practice can only be identified after the fact, in the people who improved, the theory becomes very hard to test.

What nobody seriously disputes is this: practice is necessary for expertise, it is not sufficient, and its weight varies a great deal by field. Researchers point to a broad mix of other contributors, from basic cognitive abilities and personality to the age at which people start, the quality of their coaching and the opportunities around them.

What this means for you

The research does not say that effort is pointless. It says the number of hours is a poor promise.

• Quality beats quantity. The kind of practice Ericsson described has a specific goal, immediate feedback and constant adjustment. An hour of that is not the same as an hour of repetition on autopilot.
• Expect diminishing differences at the top. Among people who have all trained hard, extra hours explain little. That is not a reason to stop, but it is a reason not to blame yourself for every gap.
• Fit matters. Because so much of the variation is not explained by practice, trying several things and noticing where you improve fastest is sensible, not a lack of commitment.
• Sustainability matters. Years of hard practice are easier when the activity absorbs you. If you are curious about the motivational side, our grit test looks at long-term perseverance, our passion test explores whether your commitment feels balanced or compulsive, and our flow test measures how often you get absorbed in what you do.

Ten thousand hours is a good story. The real finding is less tidy and more useful: practise well, practise for a long time, and keep in mind that no number of hours comes with a guarantee.