4 ms·
Kelly is special though, it's not just log utility. In fact, viewing it as maximizing log utility is ahistorical; the original derivation was in terms of inform
by spekcular 5y ago
Kelly is special though, it's not just log utility. In fact, viewing it as maximizing log utility is ahistorical; the original derivation was in terms of information theory. (The paper's title is "A new interpretation of information rate" [0].) Further, and most importantly, Kelly betting has certain favorable asymptotic properties that betting strategies motivated by other utility functions don't have. See Breiman's "Optimal gambling systems for favorable games" [1].
This point is well known in the literature, for instance see [2]:
> Perhaps one reason is that maximizing E log S suggests that the investor has a logarithmic utility for money. However, the criticism of the choice of utility functions ignores the fact that maximizing E log S is a consequence of the goals represented by properties P1 and P2, and has nothing to do with utility theory.
[0] https://www.princeton.edu/~wbialek/rome/refs/kelly_56.pdf https://www.princeton.edu/~wbialek/rome/refs/kelly_56.pdf
[1] http://www-stat.wharton.upenn.edu/~steele/Resources/FTSResources/KellyBreiman/Breiman61.pdf http://www-stat.wharton.upenn.edu/~steele/Resources/FTSResou...
[2] https://pubsonline.informs.org/doi/abs/10.1287/moor.5.2.161 https://pubsonline.informs.org/doi/abs/10.1287/moor.5.2.161
- rssoconnor 5y agoExactly. The Kelly strategy is the strategy that, with probability 1, eventually and permanently beats any other strategy. This isn't true for any other strategy and this criterion has nothing to do with utility.