Apologies as I suspect this is a basic question I've been too afraid to ask (as an academic without "real" trading experience)-- I've seen a lot of literature where trades are sized proportional to volatility raised to a power (usually -1 or -2). i.e.: Size proportional to return/vol in an attempt to normalize P&L across various opportunities and size to level playing field. Size proportional to return/vol^2, which appears to result from maximizing utility functions that make return comparable to variance. It would also seem that the inverse vol case implies a utility function that makes return and vol (as opposed to variance) comparable. I'm quite hazy on which of these choices makes more sense, since utility isn't terribly intuitive to me. Perhaps this means there's no standard answer and both are employed regularly? It would seem the choice is quite impactful, especially across opportunities with large ranges of volatilities. Fundamentally, both of these approaches seem defensible to me; is this the general perception? Is one of these choices preferable / industry standard? Are there material practical implications of this choice? Thanks!