A few days ago several bloggers felt it necessary to discuss the scientific status of economics (see Ryan Avent, Adam Ozimek, Matt Yglesias, and Jim Manzi). After reading through all those posts, a big part of me wanted to title this post: “Why do smart people discuss pointless questions?” But then I remembered that since I got a Ph.D in applied physics and blog about science studies, it would be a tad bit hypocritical. Nevertheless, here is my take on why they’re all wasting their time.
In one sense science is a brand, a very powerful and coveted brand. So it is understandable that economists want to be associated with this brand. To do so, they go through the usual routine of showing that economists care about data, change their theories under new evidence, try to make testable predictions and so on. Here’s Ryan Avent:
Is economics a science? Let me first associate myself with Adam Ozimek’s comments here. If you want to say that economics isn’t a “hard science”, that might be all right, depending on just what you mean by it. If you mean that economists can’t run lab experiments and can’t predict outcomes as accurately as, say, chemists, then that’s acceptable to me. If you mean that economists have no experiments, or don’t use the scientific method, or something of that nature, then you’re dead wrong. The currency of the economics realm is evidence. When economists do research they form hypotheses, build models, gather data, test the models against the data, and publish their conclusions. If other economists try to get similar results and fail, the original result is called into question.
All of this is (I believe) true. Economists do attempt to gather data and test their conclusions. But then again, so do historians and plumbers! And while we clearly don’t consider them scientists, we often do find their findings meaningful. So it seems to me that the important question isn’t whether or not economics is science, but whether it can be useful. Here is where, I believe, we need a bit more particularization: What economics findings are most robust? What relevance do they have for policy? And which policies? Which findings are more tentative? How do we weigh them against political exigencies?
There are two main problems with these demarcation efforts. First, it encourages us to be lazy and take shortcuts. We should be doing the hard work of determining whether a certain piece of scholarship is relevant to our specific problem and whether there is expert consensus. Instead, the above authors seem to argue: “By my simple heuristics, economics is science and thus should be trusted.” But even physics, that most scientific of sciences, contains a long history of errors and frauds. Being branded as science is no guarantee of veracity.
Perhaps the bigger, more pernicious problem is that the mere act of demarcation closes our mind to useful research that may be useful. If we have it in our mind that science and only science belongs in policy debates, we’ve really hindered ourselves. Here’s a particularly baffling passage from Jim Manzi:
I’m not arguing that economics has produced nothing of value, but rather that its most useful outputs are more like those of historians than those of biologists. Draping the cloak of “science” over its findings can often be a rhetorical strategy designed to increase the leverage of economists in policy debates.
Well, there are instances when historians should be leveraged more than biologists in policy debates. As Sarah Mayeux showed in a wonderful post on trends in American incarceration rates, a historical perspective can be illuminating. What matters is not whether our policies exclusively make use of science, but whether they exclusively make use of sound evidence and research whatever their form.