for helpful comments and suggestions. The views expressed herein are those of the author(s) and do not necessarily reflect the views of the National Bureau of Economic Research. NBER working papers are circulated for discussion and comment purposes. They have not been peerreviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

In the 1970s, large increases in the price of oil were associated with sharp de- (pre and post 1984), the distance between the empirical SVAR-based impulse response functions and those implied by the model. Our results point to two relevant changes in the structure of the economy, which have modified the transmission mechanism of the oil shock: vanishing wage indexation and an improvement in the credibility of monetary policy. The relative importance of these two structural changes depends however on how we formalize the process of expectations formation by economic agents.

Professional forecasters failed to anticipate the sharp fall in inflation in the euro area in 2013-2014. We investigate whether this forecasting failure can be partly attributed to a break in the elasticity of inflation to the output gap. Using structural break tests and time-varying parameter models, we find that this elasticity has indeed increased substantially in the past 2 years. We offer two (observationally equivalent) interpretations of this result. The first is that the increase in the cyclicality of inflation has stemmed from lower nominal rigidities or weaker strategic complementarities in price setting. A second possibility is that current output gap estimates are understating the amount of spare capacity in the economy. We estimate that, in order to reconcile the observed fall in inflation with the historical correlation between consumer prices and the business cycle, the output gap should be wider by around one third.

Between 2013 and 2014, following the recession triggered by the sovereign debt crisis, euroarea inflation decreased sharply. Although a fall in the inflation rate was to be expected, given the severity of the recession, professional forecasters failed to anticipate it. A possible explanation for this forecast failure lies in a break in the cyclicality of inflation, which was unaccounted for in forecasting models. We probe this explanation in the context of a simple backward-looking Phillips curve and find that the sensitivity of inflation to the output gap has recently increased. We rationalize this result through a structural model, in which a steepening of the Phillips curve arises either from lower nominal rigidities (a decrease in the average duration of prices) or from fewer strategic complementarities in price-setting due to a reduction in the number of firms in the economy.

In the 1970s, large increases in the price of oil were associated with sharp de- (pre and post 1984), the distance between the empirical SVAR-based impulse response functions and those implied by the model. Our results point to two relevant changes in the structure of the economy, which have modified the transmission mechanism of the oil shock: vanishing wage indexation and an improvement in the credibility of monetary policy. The relative importance of these two structural changes depends however on how we formalize the process of expectations formation by economic agents.