Jean-Paul L'Huillier

Diagnostic expectations constitute a realistic behavioral model of inference. This paper shows that this approach for expectation formation can be productively integrated into the New Keynesian framework. To this end, we start by offering a first technical treatment of diagnostic expectations in linear macroeconomic models. Diagnostic expectations generate endogenous extrapolation in general equilibrium. We show that diagnostic expectations generate extra amplification in the presence of nominal frictions; a fall in aggregate supply generates a Keynesian recession; fiscal policy is more effective at stimulating the economy; with imperfect information, diagnostic expectations generate delayed overreaction of aggregate variables. Bayesian estimation of a rich medium-scale model delivers estimates of the diagnosticity parameter that is in line with previous studies. Moreover, we find strong empirical evidence in favor of the diagnostic model

Some, but less than intended. The reason is a shift in the behavior of the private sector: Prices adjust more frequently, lowering the potency of monetary policy. We quantitatively investigate this channel across different models, based on a calibration using micro data. By raising the target from 2 percent to 4 percent, the monetary authority gets only between 0.51 and 1.60 percentage points of effective extra policy room for monetary policy (not 2 percentage points as intended). Getting 2 percentage points of effective extra room requires raising the target to more than 4 percent. Taking this channel into consideration raises the optimal inflation target by roughly 1 percentage points relative to earlier computations.

We offer a partial equilibrium perspective on the behavior of consumption in dynamic stochastic general equilibrium (DSGE) models. We consider a benchmark dynamic general equilibrium model and show that a standard calibration implies that the real interest rate is essentially fixed. One manifestation of this feature is that, with separable preferences, the reaction of consumption to total factor productivity (TFP) shocks is flat: the random‐walk permanent income hypothesis holds almost exactly, pretty much as in a partial equilibrium consumption‐savings problem. These results help explain the prominent role of aggregate demand, and how it is achieved, in modern DSGE analysis.

•The three “Slumps” were preceded by periods of major technological innovation.•We estimate a model with noisy news using data from these three episodes.•Beliefs about the long run adjust to permanent shifts in productivity with a delay.•This implies similar productivity and consumption dynamics on a 20 to 25 year window.•We emphasize a look at this data from the point of view of the medium run. The Great Recession, the Great Depression, and the Japanese Slump of the 1990s were all preceded by periods of major technological innovation, which happened about 10 years before the start of the decline in economic activity. We estimate a model with noisy news. We find that beliefs about long-run income adjust to permanent shifts in productivity with an important delay. The estimation tells a common and simple story for the observed dynamics of productivity and consumption on a 20 to 25 year window. Our analysis highlights the advantages of a look at this data from the point of view of the medium run.

We explore empirically models of aggregate fluctuations in which consumers form anticipations about the future based on noisy sources of information and these anticipations affect output in the short run. Our objective is to separate fluctuations due to changes in fundamentals (news) from those due to temporary errors in agents' estimates (noise). We show that structural VARs cannot be used to identify news and noise shocks, but identification is possible via a method of moments or maximum likelihood. Next, we estimate our model on US data. Our results suggest that noise shocks explain a sizable fraction of short-run consumption fluctuations. (JEL D84, E13, E21, E32)