Both the original "10,000 hour rule" and this rule run afoul of http://en.wikipedia.org/wiki/Sorites_paradox http://en.wikipedia.org/wiki/Sorites_paradox unless

Both the original "10,000 hour rule" and this rule run afoul of http://en.wikipedia.org/wiki/Sorites_paradox http://en.wikipedia.org/wiki/Sorites_paradox unless you rephrase the statement to something along the lines of "we have found that most people either succeed at X and continue doing it for the rest of their lives regularly or give up, and that of the people who give up, 95% of them give up before doing X for 10,000 hours" I believe the question is, "what is the mean and standard deviation of the time investment at the point when a sustained positive feedback loop is achieved?"