[mkrump]

Is it so surprising that a single factor doesn't completely (or mostly) explain performance? At the same time the paper is not saying that deliberate practice has no effect on performance.

"What explains the variance in performance that deliberate practice does not explain? There are probably many factors. "

...

"We conclude that amount of deliberate practice although unquestionably important as a predictor of individual differences in performance from both a statistical and a practical perspective—is not as important as Ericsson and his colleagues have argued."