social science can actually predict stuff
Last week, Northwestern poli sci prof Jacqueline Stevens wrote a NY Times op-ed where the main argument is that political science is lousy at predicting things. You can read responses from within the field, like the one at the Monkey Cage.
Stevens makes some good points. For example, social scientists will often dress up common sense in fancy models and jargon. But I do have one major bone of contention with Stevens’ analysis, the social sciences are actually not bad at predicting some things. For example, I can predict, in the future, that college graduates will make a lot more money, on average, than people who didn’t go to college. We’ve known this for decades. This trend will continue. In political science, there are some models that actually predict things pretty well. My favorite is the presidential votes share model, where incumbent two-party vote share is very strongly predicted by the economy.
So what gives? Does a Northwestern professor of political science not know her own field? I can’t speak for Professor Stevens, but I’ll offer a few reasons for Stevens’ skepticism. This may have to do with the lingering conflict in political science over quantitative method. There’s a bigger issue than arguing over method. Stevens picks on areas of political science where prediction is insanely hard. If you have a system with a few moving parts, prediction may be possible (e.g., predicting the correlation between education and income).
Stevens uses examples like the collapse of the Soviet Union and the rise of al-Qaeda. Global politics is a massively complex system. There’s a lot we don’t know and a lot that is hard to measure. It also has billions of moving parts and shows sudden shifts. Physics is the same way. Two billiard balls? Yeah, we got that. Predicting the next earthquake? Umm… still working on that.
Poo-poohing political scientists for not foreseeing al-Qaeda is like saying that medical science is stupid because doctors didn’t predict AIDS. Superficially true, but so very, very misguided.