system
Given the following post, respond as if you're commenting on Reddit:
human
[Economics] Why are there so many divisions in Macroeconomic thought?
gpt
The degree to which there are schools of though in **academic macroeconomics** is vastly overstated. There were major, substantive, paradigm-destroying debates in macro during the 1960s (Keynesian/Monetarist), 1970s (Keynesian/New Classical) and 1980s (New Keynesian/Real Business Cycle) but we've largely converged since the early 1990s. Almost all applied macroeconomic research is New Keynesian of some flavor, with heavy methodological influence from the New Classical and Real Business Cycle theories. Time will tell if the rise in agent-based computational macro will prove to be as paradigm-destroying as Lucas' program was forty years ago.

We have largely coalesced on a common language for modelling (DSGE), a common baseline language for causal inference (SVAR, though it's far from perfect), a common language for thinking about economic shocks (impulse, amplification, propagation), and a common language for thinking about the role of inefficiencies in the economy (wedges). By 2007, we had a few working medium-scale models that economists mostly agreed were ready for use in policy analysis (with some vocal exceptions). 

We continue to disagree, sometimes heavily, on the empirical importance of the various wedges, frictions, and market imperfections in the economy. The financial crisis has weakened the c.2007 consensus somewhat - the much-vaunted policy models weren't able to analyze large financial panics.  There is serious lack of data in macro, and an equally serious lack of good identification techniques (what natural scientists would recognize as "natural experiments"), which makes inference difficult. 

The proliferation of divisions of macro in the **public policy sphere** can be attributed to politics, lack of data, the public debate lagging the academic literature, etc.

The public lags the academic literature; that's fine. It means that in the public sphere the trifecta of Keynes, Hayek and Friedman continues to have sway on how people think about macroeconomic policy, even though all three of those thinkers had become irrelevant by 1972, their main insights absorbed into the body of academic work.  

I have a pet theory that the "divisions" in macro, that we see in the popular media, are manifestations of the general need for a "story" or "narrative," akin to political narratives, but it's just an hypothesis.