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Archive of posts filed under the Decision Theory category.

Boo! Who’s afraid of availability bias?

Just in time for Halloween: I came across this 2-minute video by Brian Zikmund-Fisher, a professor of Health Behavior and Health Education at the University of Michigan, and I took a look because I was curious what he had to say. The video is called “Why aren’t we more scared of measles?” and has the […]

Was it really necessary to do a voting experiment on 300,000 people? Maybe 299,999 would’ve been enough? Or 299,998? Or maybe 2000?

There’s been some discussion recently about an experiment done in Montana, New Hampshire, and California, conducted by three young political science professors, in which letters were sent to 300,000 people, in order to (possibly) affect their voting behavior. It appears that the plan was to follow up after the elections and track voter turnout. (Some […]

And sometimes they don’t spam you at all

I received the following email: Dear Dr. Gelman, As a way of introduction, my name is . . . and I am very interested in studying in Columbia’s PhD statistics program. For the past 2 ½ years, I’ve worked as an analyst for . . . I am writing to communicate my interest in your […]

On deck this week

Mon: 2 on chess Tues: Yes, I’ll help people for free but not like this! Wed: I love it when I can respond to a question with a single link Thurs: Sokal: “science is not merely a bag of clever tricks . . . Rather, the natural sciences are nothing more or less than one […]

Three ways to present a probability forecast, and I only like one of them

To the nearest 10%: To the nearest 1%: To the nearest 0.1%: I think the National Weather Service knows what they’re doing on this one.

On deck this week

Mon: Three ways to present a probability forecast, and I only like one of them Tues: Try a spaghetti plot Wed: I ain’t got no watch and you keep asking me what time it is Thurs: Some questions from our Ph.D. statistics qualifying exam Fri: Solution to the helicopter design problem Sat: Solution to the […]

Prediction Market Project for the Reproducibility of Psychological Science

Anna Dreber Almenberg writes: The second prediction market project for the reproducibility project will soon be up and running – please participate! There will be around 25 prediction markets, each representing a particular study that is currently being replicated. Each study (and thus market) can be summarized by a key hypothesis that is being tested, which […]

On deck this week

Tues: In one of life’s horrible ironies, I wrote a paper “Why we (usually) don’t have to worry about multiple comparisons” but now I spend lots of time worrying about multiple comparisons Wed: The Fault in Our Stars: It’s even worse than they say Thurs: Buggy-whip update Fri: The inclination to deny all variation Sat: […]

When there’s a lot of variation, it can be a mistake to make statements about “typical” attitudes

This story has two points: 1. There’s a tendency for scientific results to be framed in absolute terms (in psychology, this corresponds to general claims about the population) but that can be a mistake in that sometimes the most important part of the story is variation; and 2. Before getting to the comparisons, it can […]

Rational != Self-interested

I’ve said it before (along with Aaron Edlin and Noah Kaplan) and I’ll say it again. Rationality and self-interest are two dimensions of behavior. An action can be: 1. Rational and self-interested 2. Irrational and self-interested 3. Rational and altruistic 4. Irrational and altruistic. It’s easy enough to come up with examples of all of […]