There are three great challenges facing researchers in modern macroeconomics today, all
brought into sharp relief by the recent financial crisis. The first is to find more realistic, and yet
tractable, ways to incorporate financial market frictions into our canonical models for analyzing
monetary policy. The second is to rethink the role of countercyclical fiscal policy, particularly in the
response to a financial crisis where credit markets seize. A third great challenge is to achieve a better
cost‐benefit analysis of financial market regulation.
Prior to financial crisis, the consensus monetary policy model assumed frictionless “perfect”
financial markets in every aspect of the economy. This was in contrast to product and labor markets,
where transitory wage and price rigidities created the possibility that unemployment and capacity could
temporarily deviate from equilibrium levels, both in response to shocks and, importantly, in response to
monetary policy. The argument was that whereas financial markets might not be quite perfect, they
were far more so than labor and goods markets, and any departures from idealized perfection were of
only minor consequence. The perfect financial markets assumption may seem absurd to a lay person,
but economists often choose it because it proved a huge simplifying assumption, allowing analysis to
concentrate on say, labor markets, where distortions and imperfections were thought (by many) to be
much larger. Certainly, economists had developed sophisticated models of financial frictions and of
debt repudiation.1
However, any departure from frictionless markets where prices (including
sophisticated futures and derivative prices) move to equate demand and supply, creates considerable
complications. In addition, there was no consensus model of frictions, making it hard to know what
direction to push.
Despite the canonical models’ obviously strong assumptions, economists had been encouraged
by the apparent success of their frameworks in modeling monetary policy, not just in the United States
but around the world. The financial crisis, of course, deeply undercut that confidence. The models not
only failed to predict the crisis itself, they failed to give meaningful warning signs of any kind. Perhaps
most important, they continued to perform poorly in analyzing the aftermath of the crisis. Instead,
using historical data to development benchmark trajectories based on past deep financial crises around
the world has proven to be a far more powerful tool both for predicting the crisis and for projecting the
economy’s post crisis recovery path.2
With the benefit of hindsight, it has become apparent that part of
the consensus models’ “success” may be partly attributed to the relative ease of forecasting during
tranquil periods. The failure of the consensus models is hardly a satisfactory state of affairs,
policymakers need a more nuanced framework for analyzing their policy choices.