Polygenic Risk Scores Might Be Bullshit

A reminder that accuracy in a group does not equal accuracy for an individual.

I was really struggling to think of a good analogy to explain the glaring problem of polygenic risk scores this week. But I think I have it now. Go with me on this.

An alien spaceship parks itself, Independence Day style, above a local office building.

But unlike the aliens that gave such a hard time to Will Smith and Brent Spiner — these are benevolent, technologically superior guys. They shine a mysterious green light down on the building and then announce, maybe via telepathy, that 6% of the people in that building will have a heart attack in the next year.

They move on to the next building. “Five percent will have a heart attack in the next year”. And the next — 7%. And the next — 2%.

Let’s assume the aliens are entirely accurate. What do you do with this information?