Discussion paper

DP11521 Growth expectations, undue optimism, and short-run fluctuations

We assess the contribution of "undue optimism" (Pigou) to business-cycle fluctuations. In our analysis, optimism (or pessimism) pertains to total factor productivity which determines economic activity in the long run. We develop a new strategy to estimate the effects of optimism shocks - perceived changes in productivity which do not actually materialize. Specifically, we show that by including survey-based nowcast errors regarding current output growth in a VAR model, it is possible to identify optimism shocks. These shocks, in line with theory, generate negative nowcast errors, but raise economic activity in the short run. They account for up to 15 percent of short-run fluctuations.


Müller, G and Z Enders (2016), ‘DP11521 Growth expectations, undue optimism, and short-run fluctuations‘, CEPR Discussion Paper No. 11521. CEPR Press, Paris & London. https://cepr.org/publications/dp11521