Are Macro Shocks Second Order?

This paper addresses two fundamental macroeconomics questions. First, are macro shocks large enough to alter the course of the economy? Second, are they large enough to materially impact economic welfare? Lucas and many others have addressed these issues, but do so primarily in the context of representative agent models. We study these questions using a large-scale, general equilibrium, stochastic, overlapping generations model. We consider 80 generations overlapping in an economy buffeted by realistically calibrated total factor productivity and capital depreciation shocks. The model is solved using Marcet’s projection method taking explicit account of the full state space, which comprises 81 variables. Our findings, some recapitulated from prior studies by Hasanhodzic and Kotlikoff, suggest macro shocks are second order both with respect to their impact on aggregate variables and individual welfare. Specifically, the probability that the stochastic economy’s long-run aggregates materially deviate from their deterministic counterparts is less than one percent. Furthermore, the realized (simulated) lifetime utility of generations born in the long run rarely differs from deterministic long-run utility levels by more than 1 percent, measured as consumption-compensating differentials. These findings are supported by the model’s small equity premium. Moreover, they are essentially indifferent to the presence of a bond market. Both results suggest agents are minimally concerned with precautionary savings against these shocks. Our RBC-in-OLG findings suggest that what really moves the macroeconomy and demands attention is policy, not shocks.