Noah Smith fasst den bemerkenswert geringen Stand des gesicherten Wissens in der Makroökonomik zusammen:
"It’s hard to overstate how few solid conclusions have emerged out of a century of macroeconomic research. We don’t even have a good grasp of what causes recessions. [...]Why is macroeconomics one of the great unsolved problems in the history of human science? It isn't because macroeconomists aren’t smart enough, as anyone who has hung around them knows. It’s also not because they’re too politicized; you can find macroeconomists on every end of the spectrum. Nor is it for lack of resources being thrown at the question.The problem is data. Business cycles are few and far between. And business cycles that look similar to one another -- the Great Depression and the Great Recession, for example -- are even farther apart. It’s hard to tell whether policies have any effect, or whether those effects were about to happen anyway. The main statistical technique we have to analyze macro data -- time-series econometrics -- is notoriously inconclusive and unreliable, especially with so few data points. Comparing across countries helps a bit, but countries are all very different, and recessions can also spill over from one to another.The uncomfortable truth is this: The reason we don’t really know why recessions happen, or how to fight them, is that we don’t have the tools to study them properly. This is the situation biologists were in when they were trying to fight disease before they had microscopes. Not only did they not have the right tools, they didn’t even have any way of knowing what the right tools would be!So I can’t tell you when macroeconomics will have a real breakthrough. Will we be able to get insight from simulated economies (called agent-based models)? Will huge multiplayer online video games give us a laboratory to study recessions? Should we look at cities as economies, and gain some insight there? Or is there some other data-gathering method so different from what we do now that I can’t even imagine it?It’s easy to point and laugh and say that macroeconomics isn’t a science. It’s also easy to convince yourself that if macroeconomists just ditched their blinkered political ideologies, all would become clear. But those are comforting fantasies. The fact is, there are just some big problems that mankind doesn’t know how to solve yet."