handoflixue comments on Why We Can't Take Expected Value Estimates Literally (Even When They're Unbiased) - Less Wrong

75 Post author: HoldenKarnofsky 18 August 2011 11:34PM

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Comment author: handoflixue 19 August 2011 11:39:19PM 1 point [-]

In the Warren Buffet situation, though, we have a high certainty. It's very unlikely that Warren Buffet will actually pay us $0 or $2,000,000.

The key bit of the article:

Now say that someone estimates that action A (e.g., giving in to the mugger's demands) has an expected value of X (same units) - but that the estimate itself is so rough that the right expected value could easily be 0 or 2X. More specifically, say that the error in the expected value estimate has a standard deviation of X.

Comment author: orthonormal 20 August 2011 01:49:23AM *  6 points [-]

...and an asteroid-prevention program is extremely likely to either do nothing or save the whole world. Modeling it with a normal distribution means pretending that it's almost as likely to cause billions of deaths (compared to the baseline of doing nothing) as it is to save billions of lives.

Comment author: multifoliaterose 20 August 2011 02:02:29AM *  4 points [-]

•I think that the relevant distribution here is a log-normal distribution; this won't involve billions of deaths because it's strictly positive.

•Even if the outcome of an asteroid strike program is essentially binary there's still uncertainty as to how likely it will be successfully implemented, how likely it is to avert an asteroid strike assuming that it's implemented properly, and the likelihood of humanity surviving independently of the asteroid strike issue.

•An asteroid strike prevention program has the downside of diverting skilled labor. This may seem negligible by comparison with the upside, but the fact that the probability of impact is so small makes things less clear.

•At the level of the individual donor there's the issue of fungibility and counterfactuals (is funding an asteroid strike prevention program replacing dollars that someone else would otherwise have used to fund it? If so, what are they doing with the money instead? Is this use of money replacing that of a third person's dollars? If so, what is that third person doing instead? etc.)

These things all point in the direction of having the distribution of expected value attached to funding an asteroid strike prevention program being more diffuse than it may seem at first blush.