“The 10,000-hour rule reliably predicts the attainment of expertise in a given field.”

Throughout his book, Gladwell repeatedly refers to the “10 000-hour rule,” asserting that the key to achieving true expertise in any skill is simply a matter of practicing, albeit in the correct way, for at least 10 000 hours.

Expert performance can, however, be traced to active engagement in deliberate practice (DP), where training (often designed and arranged by their teachers and coaches) is focused on improving particular tasks. DP also involves the provision of immediate feedback, time for problem-solving and evaluation, and opportunities for repeated performance to refine behavior. Traditionally, professional expertise has been judged by length of experience, reputation, and perceived mastery of knowledge and skill. Unfortunately, recent research demonstrates only a weak relationship between these indicators of expertise and actual, observed performance.

Deliberate practice is a focused approach to skill development that involves breaking a skill into its component steps, requiring full attention and feedback, and pushing yourself outside your comfort zone. This structured approach is what separates experts from novices across virtually every domain, from music to sports to product work. Ericsson argues that simply repeating a skill over and over only helps you improve until it becomes automatic.

“The idea has become really entrenched in our culture, but it's an oversimplification,” said Brooke Macnamara, a psychologist at Case Western Reserve University in Cleveland, Ohio. “When it comes to human skill, a complex combination of environmental factors, genetic factors and their interactions explains the performance differences across people.” A study of violinists found that merely good players practised as much as, if not more than, better players, leaving other factors such as quality of tuition, learning skills and perhaps natural talent to account for the difference.

The most common misunderstanding of the 10,000-hour rule was the assumption that time spent simply using the skill was what ultimately mattered. Ericsson's research argued deliberate practice, not just doing something a lot, was what counted towards the ten thousand hours. However, other psychologists disagree, arguing that learning rates often differ between individuals in ways that can't be explained simply by practice alone.

A study of violin students at the Berlin University of the Arts, done by Anders Ericsson and his colleagues, found that the best students – who, incidentally were not yet as proficient as most professional violinists – had put in an average of 10,000 hours of practice by the time they were twenty years old. Neither of these studies suggest that simply putting in high numbers of practice hours will automatically make a person an expert. The “ten thousand hours” meme reduces expertise acquisition to a numbers game and brushes aside everything else.

A recent meta-analysis by Case Western Reserve University psychologist Brooke Macnamara and her colleagues found that deliberate practice and skill are related – but far from perfectly related. Deliberate practice hours predicted 26% of the skill variation in games such as chess, 21% for music, and 18% for sports. This is the second biggest flaw of the 10,000 Rule: It leads to a misconception that anyone can become an expert in a given area by putting in the time.

The rule claims that anyone can become an expert if they spend ten thousand hours practicing. In other words, ten thousand hours of practice is necessary and sufficient to become an expert. [...] When you think about it, that idea is incredibly silly.

Most people have heard that if you put in 10,000 hours of practice in something, you'll become an expert. Although it's not completely wrong, there are some critical flaws here. In Ericsson's newer book, Peak, he puts the record straight. The method of becoming an expert isn't to do something mindlessly over and over again for a certain amount of hours. It is through deliberate, focused and goal oriented practice.

Ericsson's 1993 study on violinists found that elite performers had accumulated an average of about 10,000 hours of deliberate practice by age 20, compared to about 5,000 hours for less accomplished peers. This was an average, not a fixed threshold, and emphasized deliberate practice over mere repetition.

In the book “Outliers”, Malcolm Gladwell popularized the notion that to become an expert in a field requires putting in 10,000 hours of practice. Gladwell asserts that achievement is driven more by practice than it is by innate talent. As evidence, Gladwell pointed to the following examples: Studies of student violinists where the development of competency (elite performer, good performer, or non-performer) was driven largely by the number of hours of practiced (10,000 hours, 8,000 hours, and 4,000 hours respectively).

For example, some players with a few hours of total practice (as few as 3,016 hours) achieved master level (highest level in chess), while others needed more time (up to 23,608 hours). In some cases, players with a huge amount of practice (more than 25,000 hours) had not reached master level. This suggests that practice alone is not enough and that the exact amount of hours depends on a variety of factors such as the age at which people start learning a skill.

Anders Ericsson and David Burkus discuss the real research behind Malcolm Gladwell's famous 10000 Hour Rule, and how true expertise emerges.

I personally think those numbers are arbitrary, and "10,000 hours" seems more like a catchy number than it is a scientific basis for recommended study.

I'm a fan of Gladwell, but have a big problem with his 10,000 hours theory. Like everyone else here, I agree that deliberate practice is the key to anything. Ten-thousand hours may not be a “rule.” It could be as easily called the 50,000 hour rule.

In fact, many experts would argue that 10,000 hours is neither necessary nor sufficient for elite sports performance. Let’s look at what we know. First, there is not a causative relationship between 10,000 hours of deliberate practice and the attainment of elite-level status.