Rebuilding Macroeconomic Theory: Addressing the Failures of New Keynesian DSGE Models Post-2008

The podcast critically examines the failure of the dominant New Keynesian Dynamic Stochastic General Equilibrium (DSGE) model to anticipate and adequately explain the 2008 global financial crisis and its prolonged aftermath. Speakers, particularly David Vines, confess to a prior "false comfort" with these models during the "Great Moderation," which presented a clean, coherent, and self-correcting view of the economy. The core argument is that these models, built on assumptions of rational expectations, optimizing agents, and microfoundations, fundamentally misrepresent how real economies behave, especially during periods of radical uncertainty and structural breaks. The post-crisis reality of persistent demand deficiency, low inflation despite unemployment, and the inability of the economy to return to its pre-shock equilibrium directly contradicts the DSGE model's predictions of strong equilibrium attractors. A key distinction is drawn between the "evolutionary" approach to macroeconomics (e.g., Phillips curve, inflation targeting) and the "revolutionary" approach of the "Midwesterners" who pushed for micro-founded, optimizing, rational expectations models, largely to discredit Keynesian economics. The speakers argue that while the latter's dominance in academia led to the New Keynesian DSGE framework, its core dogmas (rational expectations, representative agent) are deeply flawed. Nuances include the recognition that while these models might describe "good times," they utterly fail in "bad times" characterized by zero lower bound interest rates, sticky deflation, strategic complementarities among investors, low technical progress, and a lack of "sunshine" rational expectations. The discussion also highlights the importance of moving beyond the representative agent assumption to account for heterogeneity, liquidity constraints, and income uncertainty, as well as integrating financial market architecture and debt dynamics into macroeconomic models. The practical recommendations center on fundamentally re-evaluating and rebuilding macroeconomic theory for teaching and policy. This involves incorporating elements like the zero lower bound on interest rates, persistent demand-side problems, strategic complementarities in investment, and the impact of inequality. Crucially, it calls for abandoning the "straightjacket" of the Euler equation and the representative agent assumption, instead embracing heterogeneity, buffer stock saving, and a disaggregated view of household balance sheets. For policy, the insights suggest that fiscal policy becomes essential in depressed states, and that prolonged low interest rates, while stimulating debt, can ultimately constrain future consumption, questioning certain central bank policies. The need for empirically modeling consumption alongside portfolio decisions, and understanding country-specific credit market architectures, is emphasized for more effective policy advice. The broader implications extend to a paradigm shift in macroeconomics, akin to the Keynesian revolution of the 1930s or the inflation battles of the 1970s/80s. It implies a move away from a "true church" dogma in macroeconomics, making room for diverse approaches that do not strictly adhere to rational optimizing forward-looking consistency. The failure of the DSGE model highlights the critical need for models that can account for radical uncertainty, structural breaks, and complex system feedbacks, especially between the real economy and finance. This re-evaluation is not just academic but crucial for preventing future crises and guiding effective public intervention, as the Great Recession would have been far worse without it. The discussion underscores the importance of integrating micro-level insights (e.g., household balance sheets, credit constraints) into macro models to better understand aggregate phenomena.

we wouldn't be here had it not been for the failure of macroeconomics back in 2008 to spot the crash coming

Olivia Blanchard famously said the state of macroeconomics is good about three months before the world collapsed

this insistence on consistent optimizing micro founded rationality as a way of doing macro even though we are new keynesian

when you disturb this economy that we thought we understood you go right back to where you started and that doesn't go right back to where it started 15 years nowhere 10 years later

those five things are sufficient to turn that model that I described to you and simulated into a model which can stagnate in the kind of long-run Keynesian unemployment equilibrium that that picture there tends to suggest we're living in

we have to recognize there's no longer a true church in macroeconomics

the theory was outdated outdated by the asymmetric information revolution of Stiglitz and I cut off

rational expectations and in several it's the simple optimization breakdown very seriously when there are structural breaks in the economy and radical uncertainty