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Archive of posts filed under the Decision Theory category.

Big Data Needs Big Model

Big Data are messy data, available data not random samples, observational data not experiments, available data not measurements of underlying constructs of interest. To make relevant inferences from big data, we need to extrapolate from sample to population, from control to treatment group, and from measurements to latent variables. All these steps require modeling. At […]

The difference between me and you is that I’m not on fire

“Eat what you are while you’re falling apart and it opened a can of worms. The gun’s in my hand and I know it looks bad, but believe me I’m innocent.” – Mclusky While the next episode of Madam Secretary buffers on terrible hotel internet, I (the other other white meat) thought I’d pop in […]

(What’s So Funny ‘Bout) Evidence, Policy, and Understanding

[link] Kevin Lewis asked me what I thought of this article by Oren Cass, “Policy-Based Evidence Making.” That title sounds wrong at first—shouldn’t it be “evidence-based policy making”?—but when you read the article you get the point, which is that Cass argues that so-called evidence-based policy isn’t so evidence-based at all, that what is considered […]

The retraction paradox: Once you retract, you implicitly have to defend all the many things you haven’t yet retracted

Mark Palko points to this news article by Beth Skwarecki on Goop, “the Gwyneth Paltrow pseudoscience empire.” Here’s Skwarecki: When Goop publishes something weird or, worse, harmful, I often find myself wondering what are they thinking? Recently, on Jimmy Kimmel, Gwyneth laughed at some of the newsletter’s weirder recommendations and said “I don’t know what […]

Alzheimer’s Mouse research on the Orient Express

Paul Alper sends along an article from Joy Victory at Health News Review, shooting down a bunch of newspaper headlines (“Extra virgin olive oil staves off Alzheimer’s, preserves memory, new study shows” from USA Today, the only marginally better “Can extra-virgin olive oil preserve memory and prevent Alzheimer’s?” from the Atlanta Journal-Constitution, and the better […]

Nudge nudge, say no more

Alan Finlayson puts it well when he writes of “the tiresome business of informing and persuading people replaced by psychological techniques designed to ‘nudge’ us in the right direction.” I think that’s about right. Nudging makes sense as part of a package that already includes information and persuasion. For example, tell us that smoking causes […]

I’m with Errol: On flypaper, photography, science, and storytelling

[image of a cat going after an insect] I’ve been reading this amazing book, Believing is Seeing: Observations on the Mysteries of Photography, by Errol Morris, who, like John Waters, is a pathbreaking filmmaker who is also an excellent writer. I recommend this book, but what I want to talk about here is one particular […]

On deck through the first half of 2018

Here’s what we got scheduled for ya: I’m with Errol: On flypaper, photography, science, and storytelling Politically extreme yet vital to the nation healthy kids? A coding problem in the classic study, Nature and Origins of Mass Opinion A model for scientific research programmes that include both “exploratory phenomenon-driven research” and “theory-testing science” Anthony West’s […]

“Handling Multiplicity in Neuroimaging through Bayesian Lenses with Hierarchical Modeling”

Donald Williams points us to this new paper by Gang Chen, Yaqiong Xiao, Paul Taylor, Tracy Riggins, Fengji Geng, Elizabeth Redcay, and Robert Cox: In neuroimaging, the multiplicity issue may sneak into data analysis through several channels . . . One widely recognized aspect of multiplicity, multiple testing, occurs when the investigator fits a separate […]

The failure of null hypothesis significance testing when studying incremental changes, and what to do about it

A few months ago I wrote a post, “Cage match: Null-hypothesis-significance-testing meets incrementalism. Nobody comes out alive.” I soon after turned it into an article, published in Personality and Social Psychology Bulletin, with the title given above and the following abstract: A standard mode of inference in social and behavioral science is to establish stylized […]

It’s . . . spam-tastic!

We’ll celebrate Christmas today with a scam that almost fooled me. OK, not quite: I was about two steps from getting caught. Here’s the email: Dear Dr. Gelman, I hope you do not mind me emailing you directly, I thought it would be the easiest way to make first contact. If you have time for […]

Walk a Crooked MiIe

An academic researcher writes: I was wondering if you might have any insight or thoughts about a problem that has really been bothering me. I have taken a winding way through academia, and I am seriously considering a career shift that would allow me to do work that more directly translates to societal good and […]

Yes, Virginia, it can be rational to vote!

Carl Shulman correctly thought I’d be interested in this news item, “A single vote leads to a rare tie for control of the Virginia legislature”: A Republican seat flipped Democratic in a wild recount Tuesday – with the Democrat winning by a single vote – creating a rare 50-50 tie between the parties in the […]

We need to stop sacrificing women on the altar of deeply mediocre men (ISBA edition)

(This is not Andrew. I would ask you not to speculate in the comments who S is, this is not a great venue for that.) Kristian Lum just published an essay about her experiences being sexually assaulted at statistics conferences.  You should read the whole thing because it’s important, but there’s a sample paragraph. I […]

Always crashing in the same car

“Hey, remember me?  I’ve been busy working like crazy” – Fever Ray I’m at the Banff International Research Station (BIRS) for the week, which is basically a Canadian version of Disneyland where during coffee breaks a Canadian woman with a rake politely walks around telling elk to “shoo”. The topic of this week’s workshop isn’t […]

“How to Assess Internet Cures Without Falling for Dangerous Pseudoscience”

Science writer Julie Rehmeyer discusses her own story: Five years ago, against practically anyone’s better judgment, I knowingly abandoned any semblance of medical evidence to follow the bizarre-sounding health advice of strangers on the internet. The treatment was extreme, expensive, and potentially dangerous. If that sounds like a terrible idea to you, imagine how it […]

Oooh, I hate all talk of false positive, false negative, false discovery, etc.

A correspondent writes: I think this short post on p value, bayes, and false discovery rate contains some misinterpretations. My reply: Oooh, I hate all talk of false positive, false negative, false discovery, etc. I posted this not because I care about someone, somewhere, being “wrong on the internet.” Rather, I just think there’s so […]

What’s the point of a robustness check?

Diomides Mavroyiannis writes: I am currently a doctoral student in economics in France, I’ve been reading your blog fo awhile and I have this question that’s bugging me. I often go to seminars where speakers present their statistical evidence for various theses. I was wondering if you could shed light on robustness checks, what is […]

“Five ways to fix statistics”

Nature magazine just published a short feature on statistics and the replication crisis, featuring the following five op-ed-sized bits: Jeff Leek: Adjust for human cognition Blake McShane, Andrew Gelman, David Gal, Christian Robert, and Jennifer Tackett: Abandon statistical significance David Colquhoun: State false-positive risk, too Michele Nuijten: Share analysis plans and results Steven Goodman: Change […]

Poisoning the well with a within-person design? What’s the risk?

I was thinking more about our recommendation that psychology researchers routinely use within-person rather than between-person designs. The quick story is that a within-person design is more statistically efficient because, when you compare measurements within a person, you should get less variation than when you compare different groups. But researchers often use between-person designs out […]