Archive of posts filed under the Decision Theory category.

## Megan Higgs (statistician) and Anna Dreber (economist) on how to judge the success of a replication

The discussion started with this comment from Megan Higgs regarding a recent science replication initiative: I [Higgs] was immediately curious about their criteria for declaring a study replicated. In a quick skim of the info in the google form, here it is: In the survey of beliefs, you will be asked for (a) the probability […]

## Our ridiculous health care system, part 734

I went to get a coronavirus test today. We had to get the test for work, and I had no problem with that. What I did have a problem was with that, to get this test, I needed to make an appointment, fill out three forms and take an online “course” (clicking through a set […]

## Most controversial posts of 2020

Last year we posted 635 entries on this blog. Above is a histogram of the number of comments on each of the posts. The bars are each of width 5, except that I made a special bar just for the posts with zero comments. There’s nothing special about zero here; some posts get only 1 […]

## “Maybe the better analogy is that these people are museum curators and we’re telling them that their precious collection of Leonardos, which they have been augmenting at a rate of about one per month, include some fakes.”

Someone sent me a link to a recently published research paper and wrote: As far as any possible coverage on your blog goes, this one didn’t come from me, please. It just looks… baffling in a lot of different ways. OK, so it didn’t come from that person. I read the paper and replied: Oh, […]

## What we did in 2020, and thanks to all our collaborators and many more

Published or to be published articles: [2021] Reflections on Lakatos’s “Proofs and Refutations.” {\em American Mathematical Monthly}. (Andrew Gelman) [2021] Holes in Bayesian statistics. {\em Journal of Physics G: Nuclear and Particle Physics}. (Andrew Gelman and Yuling Yao) [2021] Reflections on Breiman’s Two Cultures of Statistical Modeling. {\em Observational Studies}. (Andrew Gelman) [2021] Bayesian statistics […]

## One dose or two? This epidemiologist suggests we should follow Bugs Bunny and go for two.

Joseph Delaney writes: I [Delaney] am starting to see the hot take of “why don’t we experiment with giving only one dose of an mRNA vaccine”. For example, see this. We briefly brought up one such argument a couple weeks ago, but only in the context of a discussion of something else.  I hadn’t looked […]

## Flaxman et al. respond to criticisms of their estimates of effects of anti-coronavirus policies

As youall know, as the coronavirus has taken its path through the world, epidemiologists and social scientists have tracked rates of exposure and mortality, studied the statistical properties of the transmission of the virus, and estimated effects of behaviors and policies that have been tried to limit the spread of the disease. All this is […]

## No, It’s Not a Prisoner’s Dilemma (the second in a continuing series):

The prisoner’s dilemma is the original counterintuitive hot take. Some social scientists and journalists just looove that dilemma because of how delightfully paradoxical it can be. But some situations that are described as prisoner’s dilemmas aren’t really. I discussed one such example in my article, Methodology as ideology: Some comments on Robert Axelrod’s “The Evolution […]

## Publishing in Antarctica

This one came in the email today: Dear Gelman Andrew, I am ** from ** ** Academic Publishing, a publishing house founded in Germany in 2002. We would be interested to publish a printed book based on your research in the field of Charles Murray’s Coming Apart and the measurement of social and political divisions. […]

## More on the Heckman curve

David Rea writes: A slightly more refined version of our paper on the Heckman Curve [discussed on blog last year] has been published in the Journal of Economic Surveys. The journal will also publish a response by James Heckman, as well as a reply from us. As you predicted, James Heckman’s critique of our work […]

## Risk aversion is not a thing

I came across this post by Alex Tabarrok arguing that people should be given one rather than two doses of a new vaccine. I know nothing about these vaccines but my attention was drawn to this statement from Alex: We should vaccinate 6 million people with first dose NOW. It is deadly cautious to hold […]

## In this particular battle between physicists and economists, I’m taking the economists’ side.

Palko writes, “When the arrogance of physicists and economists collide, it’s kind of like watching Godzilla battle Rodan . . . you aren’t really rooting for either side but you can still enjoy the show.” Hey! Some of my best friends are physicists and economists! But I know what he’s talking about. Here’s the story […]

## The likelihood principle in model check and model evaluation

(This post is by Yuling) The likelihood principle is often phrased as an axiom in Bayesian statistics. It applies when we are (only) interested in estimating an unknown parameter $latex \theta$, and there are two data generating experiments both involving $latex \theta$, each having observable outcomes $latex y_1$ and $latex y_2$ and likelihoods \$latex p_1(y_1 […]

## “Inferring the effectiveness of government interventions against COVID-19”

John Salvatier points us to this article by Jan Brauner et al. that states: We gathered chronological data on the implementation of NPIs [non-pharmaceutical interventions, i.e. policy or behavioral interventions] for several European, and other, countries between January and the end of May 2020. We estimate the effectiveness of NPIs, ranging from limiting gathering sizes, […]

## Literally a textbook problem: if you get a positive COVID test, how likely is it that it’s a false positive?

This post is by Phil Price, not Andrew. This will be obvious to most readers of this blog, who have seen this before and probably thought about it within the past few months, but the blog gets lots of readers and this might be new to some of you. A friend of mine just tested […]

## You can figure out the approximate length of our blog lag now.

Sekhar Ramakrishnan writes: I wanted to relate an episode of informal probabilistic reasoning that occurred this morning, which I thought you might find entertaining. Jan 6th is the Christian feast day of the Epiphany, which is known as Dreikönigstag (Three Kings’ Day), here in Zürich, Switzerland, where I live (I work at ETH). There is […]

So, there’s this idea going around that seems to make sense, but then again if it makes so much sense I wonder why they’re not doing it already. Here’s the background. A blog commenter pointed me to this op-ed from mid-November by Michael Mina, an epidemiologist and immunologist who wrote: Widespread and frequent rapid antigen […]

## Are we constantly chasing after these population-level effects of these non-pharmaceutical interventions that are hard to isolate when there are many good reasons to believe in their efficacy in the first instance?

A couple days ago we discussed issues of communicating uncertainty in a coronavirus mask experiment. That study itself is not so important, but I remain interested in the larger issues of inference and communication. I sent the discussion to epidemiologist Jon Zelner, who wrote: The struggle is real! I think this is a nice example […]

## Discussion of uncertainties in the coronavirus mask study leads us to think about some issues . . .

1. Communicating of uncertainty A member of the C19 Discussion List, which is a group of frontline doctors fighting Covid-19, asked me what I thought of this opinion article, “Covid-19: controversial trial may actually show that masks protect the wearer,” published last month by James Brophy in the British Medical Journal. Brophy writes: Paradoxically, the […]

## “We’ve got to look at the analyses, the real granular data. It’s always tough when you’re looking at a press release to figure out what’s going on.”

Chris Arderne writes: Surprised to see you hadn’t yet discussed the Oxford/AstraZeneca 60%/90% story on the blog. They accidentally changed the dose for some patients without an hypothesis, saw that it worked out better and are now (sort of) claiming 90% as a result… Sounds like your kind of investigation? I hadn’t heard about this […]