Another idea that has played a role in identifying what it is to be an expert, in some strands of expertise research and in our everyday understanding of the notion, is that expertise is determined by extensive practice. On this conception, what it is to be an expert is simply to have plugged away at something for a certain number of years. But why should the mere number of years spent practicing, rather than the level of performance reached, be a reasonable yardstick by which to measure expertise? One reason I think that some use such a criterion is that it is relatively straightforward to measure how many years someone has spent practicing a skill. Although there may still be questions about exactly when someone started engaging in extensive practice and just how extensive it was, the idea that experts are those who have practiced their endeavors for a certain number of years is comparatively objective.
For reasons similar to the criticisms of seniority-based systems of promotion, however, some reject such a criterion, because more experience does not necessarily mean better performance. Ericsson, for example, rejects this approach to defining expertise since, as he explains, “numerous empirical examples were reported where ‘experts’ with extensive experience and extended education were unable to make better decisions than their less skilled peers or even sometimes than their secretaries” (2008: p. 989).38 It is not clear, however, how damning such studies are, since they examine actions (such as psychoanalysis or picking stocks) for which there is some question about whether it is possible to develop expertise. And again, one wants to know, what criteria are being used to show that the so-called “expert” is not better than her secretary? If, for example, one thinks that superior knowledge is the defining characteristic of expertise, then the “expert” security traders are going to have quite a bit more knowledge about the stock market than their secretaries (even if the outcomes of their trades were no better). Nonetheless, mere hours or years of practice will not, for my purposes, suffice for having expertise, at least not without some further qualification of what this practice must be like. Habitual actions such as tying one’s shoes are the result of years of practice, yet I do not intend to argue against the just-do-it principle as is applied to everyday skill. Thus I cannot rely on merely the number of hours practiced as an indicator of expert level performance.