Old OB repost: Share likelihood ratios, not posterior beliefs
post by Will_Newsome · 2011-09-10T12:56:22.272Z · LW · GW · Legacy · 4 commentsContents
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http://www.overcomingbias.com/2009/02/share-likelihood-ratios-not-posterior-beliefs.html
By Anna Salamon and Steve Rayhawk
Indubitably intriguing snippet:
When I think of Aumann's agreement theorem, my first reflex is to average. You think A is 80% likely; my initial impression is that it's 60% likely. After you and I talk, maybe we both should think 70%. "Average your starting beliefs", or perhaps "do a weighted average, weighted by expertise" is a common heuristic.
But sometimes, not only is the best combination not the average, it's more extreme than either original belief.
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comment by [deleted] · 2011-09-10T15:14:26.149Z · LW(p) · GW(p)
When I think of Aumann's agreement theorem, my first reflex is to average. You think A is 80% likely; my initial impression is that it's 60% likely. After you and I talk, maybe we both should think 70%. "Average your starting beliefs", or perhaps "do a weighted average, weighted by expertise" is a common heuristic.
That's just the modesty argument, which is of highly questionable effectiveness when talking to non-rationalists.
Anyway, thanks for re-posting--this is one of my favorite OB posts.
Replies from: Will_Newsome, Xachariah↑ comment by Will_Newsome · 2011-09-10T15:29:25.942Z · LW(p) · GW(p)
It's awkward to talk about, but it is of highly questionable effectiveness in general. A 2000 rated chess player should very rarely Aumann much on the implicit opinion of a 1600; if you're playing blitz you just assume it's a blunder. (If you're playing rapid you have more time; it's like the difference between a real-time conversation and an internet discussion.) Sure, they're both in the category "decent chess players", and in far mode 400 rating points doesn't feel like a big difference---and over the course of months it's very surmountable---but during the game it's really important to keep the strength difference in mind. This is why it's really sad that "rationality" doesn't (can't) have a martial-arts-style belt system. Everybody prides themselves on their ability to think effectively about arbitrary topics and thus any claim of inequality is at best awkward and at worst lastingly offensive.
↑ comment by Xachariah · 2011-09-12T00:09:39.666Z · LW(p) · GW(p)
That's just the modesty argument, which is of highly questionable effectiveness when talking to non-rationalists.
As a rationalist, I disagree and I am 170% certain of this fact. We should average our certainty and improve our Pareto-Efficiency until you agree with me.
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