Seminal models of herd behaviour and informational cascades point out existence of negative information externalities, and propose to ?destroy? information in order to achieve social improvements. Although in the last years many features of herd behaviour and informational cascades have been...

This paper performs a welfare analysis of economies with private information when public information is endogenously generated and agents can condition on noisy public statistics in the rational expectations tradition. We find that equilibrium is not (restricted) efficient even when feasible...

We show that the stock market may fail to aggregate information even if it appears to be efficient and that the resulting decrease in the information content of stock prices may drastically reduce welfare. We solve a macroeconomic model in which information about fundamentals is dispersed and...

We study social learning in a large population of agents who only observe the actions taken by their neighbours. Agents have to choose one, out of two, reversible actions, each optimal in one, out of two, unknown states of the world. Each agent chooses rationally, on the basis of private...