The main task of this post is to try and answer the following question: why do schools of thought seem to fragment mainstream macroeconomics but not microeconomics? However before tackling that issue, I need to clear some ground raised by some interesting comments on my earlier posts on this issue.
One point I did not make clear enough in my earlier discussion is a distinction between mainstream and heterodox economics. The latter might include neo-Marxists, post Keynesians, Austrians and others. My concern was about mainstream macroeconomics becoming fragmented into schools of thought. I can see why those challenging the mainstream might find schools of thought both convenient and useful. I also think it is very important that the mainstream should be continually challenged.
I also may not have emphasised enough the downside of the microfoundations project. I do worry that it may help to exclude good ideas, as James Galbraith suggests, and have written about how this could be dangerous for policymakers who rely on the mainstream. However I still believe that microfoundations, if interpreted flexibly, bring net benefits. But that is not the focus of what I wanted to say on schools of thought.
The success of the microfoundations project is also why I agree with Steve Williamson that academic work in macro is probably not as fragmented as it was in the 1970s. (I was not an academic at the time, so I cannot be sure.) In that sense, academic macroeconomists when doing academic work can still locate what they do within a common, mainstream framework. We all use models that abstract from many things to focus on what we think is important for some particular issue, and we receive criticism about whether those abstractions are valid or not. My concern about schools was more with the interface between academia and policy, which includes the advice academics give, what economic journalists write, and what politicians pick up.
The kind of thing I had in mind here include politicians thinking that austerity would not increase unemployment, because those that worried that it would were from the same misguided Keynesian school that opposed Margaret Thatcher’s monetarism in 1981. Journalists who find it easier to slot every debate into one between schools rather than address issues on their merits. And academics who attempt to argue that certain views are not worthy of consideration because they were confined to the dustbin 30 years earlier. Jonathan Portes gave similar examples in his post.
One of the interesting things about schools of thought in mainstream macroeconomics is that there does not seem to be anything similar in microeconomics. Now such a generalisation invites counterexamples. Some might point to the debate over the methodology of behavioural economics, for example. However most of my academic colleagues who I have road tested this idea on do agree that macroeconomics seems more prone to schools fragmentation than microeconomics. If this is true today, it is strange, because macroeconomics has become microfounded.
One simple answer to this paradox is that schools of thought are associated with macroeconomic crises, and macro synthesis follows periods of calm. Keynesian theory itself was born out of the Great Depression. The first Neoclassical Synthesis arose from the period of strong growth and low inflation in the post-war period. Monetarism gained strength from the rapid inflation of the 1970s. The more recent synthesis may be a child of the Great Moderation, and now we have the Great Recession, schools of thought have returned. Because these crises are macroeconomic, and there are no equivalent crises involving microeconomic behaviour or policy, then fragmentation of the mainstream into schools will be a macro, not micro, phenomenon.
Attractive though this account seems, I think it misses some important points. As one of the comments on my original post pointed out, the New Neo-classical Synthesis was in many ways a celebration of New Keynesian theory which was not shared by many freshwater departments in the US. Now I think there are good reasons why New Keynesian economists might have imagined that their analysis was an uncontested part of the mainstream. As I noted here, it is used in nearly all central banks as their main tool in carrying out monetary policy. With monetary policy somewhat depoliticised through central bank independence, the Great Moderation allowed this division among academic departments to remain dormant.
On the other side, there was a belief that New Classical economics had been revolutionary: a successful counter-revolution against Keynesian ideas. Once again there were good reasons to support this belief. Nick Rowe in his comment on my Anti-Keynesian School post noted how many Monetarist ideas, opposed at the time by many Keynesians, were now part of the mainstream. We could do the same for the battles between New Classical and Keynesian economists: on consumption, rational expectations, the Lucas critique and more, traditional Keynesians had unsuccessfully opposed New Classical ideas. Furthermore, many of the leaders of New Classical thought did not want to update Keynesian thinking, they wanted to destroy it.
There is a lot more that could be said here, but it would lead me to the conclusion that this counter-revolution failed. It led to fundamental and largely progressive changes in Keynesian analysis, and macroeconomics more generally, and Keynesian analysis survived and prospered. Yet, for many reasons including ideological ones, the would-be counterrevolutionaries did not want to give up their counterrevolution.
So, perhaps unlike the first (post-war) neoclassical synthesis, the New Neoclassical Synthesis was partial in terms of its coverage among academics. This incompleteness was not apparent during the Great Moderation, because the synthesis was applied in nearly every central bank. The fault lines only became apparent when monetary policy became relatively impotent at the zero bound after the Great Recession, and fiscal stimulus was used both in the US and UK. Once that happened, what I called the Anti-Keynesian school re-emerged.
This back story is important, because it raises the possibility of an optimistic (from a Keynesian point of view) way forward. This is that the New Neo-Classical synthesis becomes complete. (For possible signs that this has already begun, see here.) The microfoundation of macroeconomics does logically imply that mainstream macro should be as free from alternative schools as microeconomics. This would require freshwater macroeconomists to recognise that New Keynesian models are essentially RBC models plus sticky prices, and that the addition of price rigidity was not that offensive. All would recognise that the conditions in which fiscal policy was a major stabilisation tool were either rather unusual (the zero bound), or geographically remote (monetary union), and so not something to get so worked up about. Freshwater economists would come to realise that demand denial just did not make academic sense.
I fear a more realistic conclusion is that the Keynesian/Anti-Keynesian division is always going to be with us, because it reflects an ideological divide about state intervention. (For some supporting evidence, see here.) That divide occurs all the time in microeconomics, but because it involves arguing about many different externalities or imperfections it does not lend itself to fragmentation into schools. In macro, however, there is one critical externality to do with price rigidity, and so disagreements about policy can easily be mapped into differences about theory. Demand denial is attractive because it gives a non-ideological justification for what is essentially an ideological position about economic policy.