In 1993, a group of researchers found that practice accounts for 80 percent of the difference between elite and average musicians. This finding, says the New York Times, kicked off the idea of the so-called "10,000 hour rule" - the time needed to expertly master a skill - as popularized by author Malcolm Gladwell.

In truth, however, the science of what it takes to be the very best (like no one ever was) is much shakier than popular understanding would imply. Since that landmark paper came out more than two decades ago, researchers have continued to debate what matters most to real mastery: practice or innate talent.

Now, a new study that tried to analyze all of the relevant research on the topic has come down squarely in the "natural ability" camp.

As the Times writes, the paper analyzed the results of nearly 90 other studies carried out across disciplines ranging from sports to the arts to academia. The authors found that practice only justifies at most 20 to 25 percent of the difference between elite performers and those who are good, but not great. Natural talent, those authors concluded in their study, is more important than practice.

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.

Other researchers, however, cry foul. Some say that the authors didn't define practice clearly enough, lumping in casual play with serious lessons and thus diluting true practice's effect. Others say that there are important factors that the literature doesn't capture very well, such as the age at which someone began learning a new skill; whether they have a driven personality; and the number of tournaments, tests, performances or other by-memory challenges that people put themselves through. Still others, the Times continues, say that varying the location and timing of practice can make a difference in how effective it is.

The authors of the new paper, however, are sticking to their findings. They say that those nuances don't change the results. As the Times writes: "Like most branches of the nature-nurture debate, this one has produced multiple camps, whose estimates of the effects of practice vary by as much as 50 percentage points."