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Prediction market does not imply causation

Unless you're careful, conditional prediction markets have all the same problems as observational studies.

We all want to make good decisions. But it’s hard because we aren’t sure what’s going to happen. Like, say you want to know if CO₂ emissions will go up in 10 years. One of our best ideas is to have people bet. For example, I might wager my $4...

The conspiratorial Monty Hall problem

What if you and Monty decide to cheat?

The Monty Hall problem has now been a pox on humanity for two generations, diverting perfectly good brains away from productive uses. Hoping to exacerbate this problem, some time ago I announced a new and more pernicious variant: What if you and Monty try to cheat?

Social dynamics of bluetooth speakers

A mathematical model of who turns on their bluetooth speaker at the beach.

Say you're at a park or a beach. How many people will have bluetooth speakers on? It seems to me there are three types of people: The main characters always turn on their speakers regardless of what anyone else is doing. The haters never turn on a speaker, no matter...

It’s perfectly valid for a trait to be more than 100% heritable

What heritability really is: A fluid statistic that changes whenever society changes.

All psychological traits are heritable. This is the best replicated finding in all of behavioral genetics. Some recent numbers include: Religiosity: 44% Schizophrenia: 79% Big five personality traits: ~40% But what, exactly, does "heritability" mean? I used to have a mental model something like this: Each person has some number...

Simpson's paradox all the way down

Visualizes Simpson's paradox, and shows how it's a deeper problem than many people realize.

It's hard to get into Oxford. Is it easier if your parents are rich? In 2013, The Guardian showed noticed something disturbing: Students from (expensive) independent schools were accepted more often that students from state schools (28% vs 20%). Of course, a natural question to ask is, did students from...

Making the Monty Hall problem weirder but obvious

It's this simple: Do you want what's behind one door or the other nine?

Here’s an Obvious Problem: There are 10 doors. A car is behind a random door, goats behind the others. Do you want what’s behind door 1, or what’s behind all the other doors? That’s easy, right? Well, how about the Monty Hall problem? There are three doors. A car is...