In 2008, Malcolm Gladwell's hugely popular book Outliers brought attention to a previously little known study of violin students at a German music academy. That study was a major contributor to the literature on expert performance, but wasn't widely known until Gladwell took a result from the finding and branded it the "10,000-hour rule." As the rule has been popularly understood, all it takes to become a world-class expert in any field is 10,000 hours of practice.

To his credit, that isn't exactly what Gladwell said, nor was he writing about the 10,000- hour rule to create a roadmap for everyone to become an expert. But it's what most of us remember as the lesson from Outliers. He made a compelling case, and as evidence put up a diverse set of examples, from the Berlin violinists to Bill Gates to the Beatles.

I recently interviewed Anders Ericsson, the lead researcher in that now-famous violinist study, and he set the record straight on what Gladwell, and all of us, missed about the 10,000-hour rule.

First, it's not actually Ericsson's rule, its Gladwell's. "Some people don't realize that it was Malcolm Gladwell who actually came up with this idea of a 10,000-hour rule. I think he emphasized almost the magical aspect that when individuals have spent 10,000 hours, then they actually are able to make contributions, like the more outstanding individuals," Ericsson says. "He misread that as every one of them had actually spent at least 10,000 hours [practicing], so somehow they passed this magical boundary." Instead, some students had more and some had less.

Second, 10,000 hours didn't turn them into world-class performers. Ericsson and his team used "promise for international performance as violinists" as the guiding factor for categorizing this group. But potential to be world class is not the same thing as being world class. As Ericsson writes in Salon, "They were very good, promising students who were likely headed to the top of their field, but they still had a long way to go at the time of the study."

The third, and perhaps most important, distinction between what Gladwell popularized and what Ericsson's research showed is that it's not about hours of practice, it's about deliberate practice. "That's a kind of practice where you're not actually doing your job, you're actually taking time where you're focusing in on trying to improve," Ericsson says. "In particular, when you do that under the guidance of a master teacher, so the teacher would be able to actually tell you what is going to be the next step here in your development. That is the kind of practice that we talked about as being essential to reach the highest level of performance."

Gladwell and Ericsson agree that talent is the product of rigorous practice. In Outliers, Gladwell aimed to show you that, but he didn't show you how. Ericsson, however, picks up where Gladwell leaves off by outlining what deliberate practice is and how to put it to work for you. But to get there, we first have to come to terms with how to spend 10,000 hours and what we'll get after we've spent them.