I had the same torn reaction, but upon reading the full text (thanks, Gwern!) I'm no longer conflicted: it's not really a new study, so much as it is a systematic review of roughly a decade of relevant literature. Malcolm Gladwell seems to have based his claims mainly on a widely-cited Hot New Study from 1993, which has since turned out to have been overblown: later studies on the importance of deliberate practice have almost all come up with lower values for the correlation between deliberate practice hours and performance.
So, it looks like ignoring Malcolm Gladwell was the right answer here. It usually is.
> later studies on the importance of deliberate practice have almost all come up with lower values for the correlation between deliberate practice hours and performance.
What's also really interesting is the differences in the kind of data used to measure deliberate practice: daily logs, which you'd think be the most accurate, showed the least correlation with performance, while retrospective interviews showed the most. Biases in recollection or researcher allegiance?
So, it looks like ignoring Malcolm Gladwell was the right answer here. It usually is.