It's an often repeated internet certainty that, to be truly good at something, you need to practice for 10,000 hours. As far as I have been able to ascertain, this theory (or hypothesis?) gained popularity with Malcolm Gladwell's book Outliers.
Is there any factual basis for this claim, other that the fact that more practice is better?
This theory has been mentioned in other questions and answers right here on skeptics:
Well it's hardly a full-scale scientific trial, but someone is actually putting this to the test right now: there is a Dan McLaughlin who has set out to do 10,000 hours of deliberate golf practice from complete novice... and we'll just have to wait and see how good they end up. So far they've done around 3,300 hours.
The Freakonomics people have some commentary on his programme here and some writing on Ericcson's theories here. Reading the Ericsson paper they cite, the only mention of 10,000 hours seems to be
In the following discussion we reexamine the evidence ... for the role of innate differences in the attainment of expert performance. The dichotomy between characteristics that can be modified and those that cannot may not be valid when we examine the effects of over 10,000 h of deliberate practice extended over more than a decade.
and the one cited by @Josh's answer also contains only one mention:
By the age of 20, the best musicians had spent over 10,000 hours practicing, which averages 2,500 and 5,000 hours more than two less-accomplished groups of musicians at the same academy, respectively.
So really all this 10,000 hours figure is, is a guide to the magnitude of the amount of practicing needed to significantly influence expertise, at least in Ericcsons's studies. However, it's a memorable enough soundbite that it seems to have taken on a life of it's own. Further, once the the "deliberate practice" aspect has been forgotten (e.g see comments on original post!) people find it useful as a tool to justify complacency ("well I've been doing this job for a few years and at least 10000 hours easily; so of course I must be an expert now").
I think the 10,000 hours of practice you are referring to is the idea that Anders Ericsson talks about in some of his work on expertise, made popular by Malcolm Gladwells book "Outliers". The idea is not just 10,000 hours of repetitive practice, but Ericsson talks about the concept of "deliberate practice". It's practice that has the qualities of:
Very different than mindlessly doing something automatically for 10,000 hours.
I don't know how important the actual number 10,000 is, I think there's some debate surrounding that, but if you practice with those qualities in mind for a long period of time you will most likely improve more than you would if you mindlessly repeat something for the same amount of time.
Ericsson wrote an article explaining some of what I am talking about better than I can. [PDF]
If you are a programmer, there is an old yet well-known article by Peter Norvig, Director of Research at Google. It's called Teach Yourself Programming in Ten Years.
Several studies are quoted, as well as the Malcolm Gladwell report. The 10 000 hours are the result of a study on students at the Berlin Academy of Music.
