Knowledge that Transforms

In the competitive model, externalities lead to inefficiencies, and inefficiencies increase with the size of externalities. However, as argued by Coase, these problems may be mitigated in a decentralized system through voluntary coordination. We show how coordination is limited by the combination of two factors: respect for individual autonomy and the existence of private information. Together they imply that efficient outcomes can only be achieved through coordination when external effects are relatively large. Moreover, there are instances in which coordination cannot yield any improvement at all, despite common knowledge that social gains from agreement exist. This occurs when external effects are relatively small, and this may help to explain why coordination is so seldom observed in practice. When improvements are possible, we describe how simple subsidies can be used to implement second-best solutions and explain why standard solutions, such as Pigovian taxes, cannot be used. Possible extensions to issues arising in the structure of research joint ventures, assumptions in the endogenous growth literature, and the location of environmental hazards are also described.

A general-equilibrium model is developed to highlight the link between neo-Keynesian mod-els of unemployment and recent results on the constrained sub-optimality of competitive economies with incomplete asset markets. Although the model deviates from the Arrow-Debreu paradigm only by the absence of some contingent claims, the competitive equilibrium exhibits under-employ-ment and balanced-budget fiscal policies have Keynesian effects which are Pareto improving. I.

This paper considers a representative agent model of asset prices based on a recursive utility specification. A constant elasticity of intertemporal substitution is assumed but the risk-preference component of utility is restricted only by qualitative, non-parametric regularity conditions. A principal contribution is to determine the exhaustive implications of this semiparametric recursive utility model for the one-step ahead joint probability distribution for consumption growth and asset returns. It is also shown, in contrast to the claims of previous studies, that the generalization from expected utility to recursive utility contributes substantially to the resolution of the equity premium puzzle.