Comparing Four Models of Aggregate Fluctuations due to Self-Fulfilling Expectations

This paper compares four equilibrium business cycle models with increasing returns to scale production technologies that allow for aggregate fluctuations due to self-fulfilling expectations. Necessary and sufficient conditions for the existence of stationary sunspot equilibria are derived. Numerical examples demonstrate that the degree of increasing returns necessary for the existence of stationary sunspot equilibria lies in the upper range of available empirical estimates. The paper also shows that persistent fluctuations are not a necessary property of these four models when the only source of fluctuations is changes in people's expectations about the future path of the economy. Journal of Economic Literature Classification Numbers: E32, D43. 1997 Academic Press