Overview for RolfAndreassen - Less Wrong

RolfAndreassen on Post ridiculous munchkin ideas!

2013-05-12T23:23:47.136352+10:00

75% is only an example. Adjust according to what you can actually manage to save. If you are paid $100k, as is by no means impossible for this demographic (and in fact is rather easy if you're a two-income household)m then 75% is easily doable. At $25k, which is also by no means impossible for our demographic, then yes, the 75% savings rate becomes difficult.

RolfAndreassen on Post ridiculous munchkin ideas!

2013-05-12T22:31:55.544897+10:00

Please read "without assuming any real gains from..."

RolfAndreassen on Post ridiculous munchkin ideas!

2013-05-11T04:59:46.953330+10:00

Obvious idea is obvious: Save and invest a very large percentage of your income - I'm at 25%, but I'm not very ambitious. At 75% you can retire for three years for every year you work, even without assuming any gains from investment income or any other sources of income. If you are 30 and reasonably established in your career, this means you can work for ten years and then retire.

RolfAndreassen on Rationality Quotes May 2013

2013-05-09T05:38:42.732363+10:00

It is of course very difficult to extract any precise numbers from a political discussion. :) However, if you click through some of the links in the article, or have a look at the followup from today, you'll find McArdle quoting predictions of tens of thousands of preventable deaths yearly from non-insured status. That looks to me like a pretty big hazard rate, no?

RolfAndreassen on Rationality Quotes May 2013

2013-05-09T03:52:12.626910+10:00

Er, yes, fine, but... to the extent that the study shows anything, it shows that the positive results of these effects, if they exist, are consistent with zero. Can we please discuss the data, now that we have some, and not theory?

RolfAndreassen on Rationality Quotes May 2013

2013-05-09T03:50:23.987443+10:00

can one say "pre-hoc"?

Well, if not, one ought to be able to. I hereby grant you permission! :)

RolfAndreassen on Rationality Quotes May 2013

2013-05-09T03:48:41.743020+10:00

If this were the only medical study in all of history, then yes, a non-significant result should cause you to update as your quote says. In a world with thousands of studies yearly, you cannot do any such thing, because you're sure to bias yourself by paying attention to the slightly-positive results you like, and ignore the slightly-negative ones you dislike. (That's aside from the well-known publication bias where positive results are reported and negative ones aren't.) If the study had come out with a non-significant negative effect, would comrade Drum have been updating slightly in the direction of "Medicaid is bad"? Hah. This is why we impose the 95% confidence cutoff, which actually is way too low, but that's another discussion. It prevents us from seeing, or worse, creating, patterns in the noise, which humans are really good at.

The significance cutoff is not a technique of rationality, it is a technique of science, like blinding your results while you're studying the systematics. It's something we do because we run on untrusted hardware. Please do not relax your safeguards if a noisy result happens to agree with your opinions! That's what the safeguards are for!

Then also, please note that Kevin Drum's prior was not actually "Medicaid will slightly improve these three markers", it was "Medicaid will drastically reduce mortality". (See links in discussion with TheOtherDave, below). If you switch your priors around as convenient for claiming support from studies, then of course no study can possibly cause you to update downwards. I would gently suggest that this is not a good epistemic state to occupy.

RolfAndreassen on Rationality Quotes May 2013

2013-05-09T03:39:15.226112+10:00

Again, the original point McArdle is making is that "consistent with zero" is just completely not what the proponents expected beforehand, and they should update accordingly. See my discussion with TheOtherDave, below. A small effect may, indeed, be worth pursuing. But here we have a case where something fairly costly was done after much disagreement, and the proponents claimed that there would be a large effect. In that case, if you find a small effect, you ought not to say "Well, it's still worth doing"; that's not what you said before. It was claimed that there would be a large effect, and the program was passed on this basis. It is then dishonest to turn around and say "Ok, the effect is small but still worthwhile". This ignores the inertia of political programs.

RolfAndreassen on Rationality Quotes May 2013

2013-05-09T03:30:33.464076+10:00

How large was your prior for "insurance helps some and harms others, and we should try to figure out which is which" before that was one possible way of rescuing insurance from this study? That sort of argument is, I respectfully suggest, a warning signal which should make you consider whether your bottom line is already written.

RolfAndreassen on Rationality Quotes May 2013

2013-05-08T09:01:52.038887+10:00

which intuitively seem big enough to be part of an across-the-board health improvement that passes cost-benefit muster.

This would be much more convincing if you reported the costs along with the benefits, so that one could form some kind of estimate of what you're willing to pay for this. But, again, I think your argument is motivated. "Consistent with zero" means just that; it means that the study cannot exclude the possibility that the intervention was actively harmful, but they had a random fluctuation in the data.

I get the impression that people here talk a good game about statistics, but haven't really internalised the concept of error bars. I suggest that you have another look at why physics requires five sigma. There are really good reasons for that, you know; all the more so in a mindkilling-charged field.