Greg Mankiw gave a presidential address at the Eastern Economic Association meetings in Philadelphia over the weekend on distribution effects of tax policy, pushing his height story. But that was less interesting than another session chaired by Mark Setterfield of Trinity College where Mankiw, author of the most widely used textbooks in undergrad macroeconomics, was in the audience for "Macroeconomic Theory and Macroeconomic Pedagogy: Rethinking Undergraduate Macroeconomics Instruction." Mark has coedited a volume with Giuseppe Fontana of the same title as the opening part of the session title, recently out from Routledge. While not everybody in the book is of the persuasion, most of the presenters were Post Keynesians, including Malcolm Sawyer of Leeds University and John Smithin of York University in Ontario, as well as several in the audience such as Tom Palley, who engaged in vigorous discussion.
Much of the book and the discussion focused on the so-called "new concensus" three equation model, which are an IS curve giving aggregate demand, a Phillips curve, and than a policy curve essentially implying a Taylor rule with the central bank setting nominal interest rates. This implies endogenous money, a concept much liked by many Post Keynesian economists, although many argue it holds more broadly than just when central banks exogenously set interest rates. Sawyer pursued the endogenous money argument further, and Smithin offered an alternative three equation model with the Phillips curve and the Taylor rule replaced by short and long run supplies of inflation equations. It was over whether the Post Keynesians had any alternatives to the new consensus model and also could explain hyperinflation where Mankiw stepped in to question. Smithin replied with his three equation model, although the equivalent of the IS curve seemed much more complicated than the usual variety, too much so for a Principles text anyway, if not perhaps a higher level one. Mankiw did not seem convinced.
A sub-text was that it is unclear if these Post Keynesian models did much better in explaining recent events than the now silly looking standard model. Most observers would say that the big winner in all this has been Hyman Minsky, generally labeled a Post Keynesian, although he did not particularly like the label (and Paul Davidson claims he was not one, or a proper one). A couple of the chapters in the book, if not the session, attempt to bring Minsky in, but it is unclear that all this has been resolved clearly. In another session at the conference, another author from the book, Marc Lavoie, agreed that in a world where central banks lose control of actual interest rates as they fall below corridor levels, the standard endogenous money model may be out the window along with the more conventional model. It is too bad that Minsky is no longer with us when we need him (and he used to be a regular attender of the EEA meetings, sigh... ).