If your loss function is severely skewed, you do NOT want to be unbiased.


Actions is what you should care about -- if these are determined, your beliefs (which in this case do not pay rent) don't matter much.

So why would I want to bias myself after I've decided to take excessive precautions?

I think we're in agreement btw, we care about actions, and if you have a very skewed loss function then it is rational to spend a lot of effort on improbable scenarios in which you lose heavily, which from the outside looks similar to a person with a less skewed loss function thinking that those scenarios are actually plausible. I was just trying to point out that DanielLC's reply was correct and your previous one is not - even with a skewed loss function this should not produce feedback to the actual beliefs, only to your actions. So no, you DO want to be unbiased, it's just that an unbiased estimate/posterior distribution can still lead to asymmetric behaviour (by which I mean spending an amount of time/effort to prepare for a possible future disproportionate to the actual probability to this future occurring).

Well, let me unroll what I had in mind.

Imagine that you need to estimate a single value, a real number, and your loss function is highly skewed. For me this would work as follows:

  • Get a rough unbiased estimate
  • Realize that I don't care about the unbiased estimate because of my loss function
  • Construct a known-biased estimate that takes into account my loss function
  • Take this known-biased estimate as the estimate that I'll use from now on
  • Formulate a course of action on the basis of the the biased estimate

The point is that on the road to deciding on the c... (read more)

Rationality Quotes Thread March 2015

by Vaniver 1 min read2nd Mar 2015235 comments


Another month, another rationality quotes thread. The rules are:

  • Please post all quotes separately, so that they can be upvoted or downvoted separately. (If they are strongly related, reply to your own comments. If strongly ordered, then go ahead and post them together.)
  • Do not quote yourself.
  • Do not quote from Less Wrong itself, HPMoR, Eliezer Yudkowsky, or Robin Hanson. If you'd like to revive an old quote from one of those sources, please do so here.
  • No more than 5 quotes per person per monthly thread, please.
  • Provide sufficient information (URL, title, date, page number, etc.) to enable a reader to find the place where you read the quote, or its original source if available. Do not quote with only a name.