How close is this notion to our common understanding of expertise?

As this is a stipulative definition (that is, I am merely specifying what I mean by “expert” and not trying to say what an expert truly is), I am not bound to define the term in a way that comports with any common ways of understanding the notion. However, if my stipulation does approximate one or more of our various understandings of expertise, all the better. And I do think that many of those individuals whom we think of as experts—for example, many professional-level performing artists, athletes, and chess players—are covered by my criterion. However, I also think that my conception of expertise does not line up with some common ways of thinking about what it is to be an expert. And although I am no doubt better at finding flaws in other people’s definition of what counts as an expert—and indeed, though I did not mention it in the introduction, perhaps a particularly salient defining characteristic of a philosopher is the ability to criticize other’s views—let me try to identify some of the ways in which my criterion might not line up with other notions of ‘expert.’ I once heard my cousin, the political scientist Gerald Rosenberg, explain that as long as you acknowledge that what you are eating breaks a Kosher law, it’s still Kosher. And although I cannot comment on Gerry’s counsel, I have no illusions that by owning up to some of the ways in which my definition of expertise diverges from ordinary understandings of it, I will have made my definition Kosher, as it were. Nonetheless, in indicating some such divergences as well as possible objections to the view, I hope to help those who prefer to understand expertise in other ways see to where my theory would need adjusting.