Andrea Prat

The Wrong Kind of Transparency

In a model of career concerns for experts, when is a principal hurt from observing more information about their agent? This Paper introduces a distinction between information on the consequence of the agents action and information directly on the agents action. When the latter kind of information is available, the agent faces an incentive to disregard useful private signals and act according to how an able agent is expected to act a priori. This conformist behaviour hurts the principal in two ways: the decision made by the agent is less likely to be the right one (discipline) and ex post it is more difficult to evaluate the agents ability (sorting). The Paper identifies a necessary and sufficient condition on the agent signal structure under which transparency on action is detrimental to the principal. The Paper also shows the existence of complementarities between transparency on action and transparency on consequence. The results on the distinction between transparency on action and transparency on consequence are then used to interpret existing disclosure policies in politics, corporate governance, and delegated portfolio management.

The Political Economy of Mass Media

We review the burgeoning political economy literature on the influence of mass media on politics and policy. This survey, which covers both theory and empirics, is organized along four main themes: transparency, capture, informative coverage, and ideological bias. We distill some general lessons and identify some open questions.

Games played through agents

We introduce a game of complete information with multiple principals and multiple common agents. Each agent makes a decision that can affect the payoffs of all principals. Each principal offers monetary transfers to each agent conditional on the action taken by the agent. We characterize pure-strategy equilibria and we provide conditions-in terms of game balancedness-for the existence of an equilibrium with an efficient outcome. Games played through agents display a type of strategic inefficiency that is absent when either there is a unique principal or there is a unique agent. Copyright The Econometric Society 2003.

Risk Taking and Optimal Contracts for Money Managers

We study delegated portfolio management when the agent controls the riskiness of the portfolio. Under general conditions, we show that the optimal contract is simply a bonus contract: the agent is paid a fixed sum if the portfolio return is above a threshold. We derive a criterion to decide whether the optimal contract induces excessive or insufficient risk. If a deviation from efficient risk taking causes a large (small) reduction in the expected return of the portfolio, the optimal contract induces excessive (insufficient) risk. In other words, the cheaper it is to play with risk, the less risk the agent takes. Copyright 2003 by the RAND Corporation.

The Price Impact of Institutional Herding

In this paper we develop a simple theoretical model to analyze the impact of institutional herding on asset prices. A growing empirical literature has come to the intriguing conclusion that institutional herding positively predicts short-term returns but negatively predicts long-term returns. We offer a theoretical resolution to this dichotomy. In our model, career-concerned money managers interact with profit-motivated proprietary traders and security dealers endowed with market power. We show that the reputational concerns of fund managers imply an endogenous tendency to imitate past trades, which impacts the prices of the assets they trade. In our main result, we show that institutional herding positively predicts short-term returns but negatively predicts long-term returns. Our theory thus provides a simple and unified framework within which to interpret the empirical literature on the price impact of institutional herding. In addition, our paper generates several new testable predictions linking institutional herding behavior, trading volume, and the time-series properties of stock returns.

Institutional Trade Persistence and Long-term Equity Returns

How does the trading behaviour of institutional money managers affect stock prices? In this paper we document a robust relationship between the net trade patterns of institutional money managers and long term equity returns. Examining quarterly data on US institutional holdings from 1983 to 2004, we find evidence that stocks that have been persistently bought (sold) by institutions in the past 3 to 5 quarters underperform (overperform) the rest of the market in the next 12 to 30 months. Our results are of a similar magnitude to, but distinct from, other known asset pricing anomalies. Furthermore, we find that institutional investors show an aggregate tendency to trade in the direction of past institutional trades, buying stocks that have been persistently bought and selling stocks that have been persistently sold. We present a simple model of career-concerned trading by delegated portfolio managers that generates results consistent with our empirical findings.

Should a team be homogeneous

Abstract Should an organization hire people with similar backgrounds or with different backgrounds? We formulate this question within the framework of team theory. The team is formed by n agents. The type of each agent is endogenous and determines his information structure and his cost for the team. We show that the sign of complementarity between jobs determines workforce homogeneity. With positive complementarities, the team should be composed of agents of the same type, while, with negative complementarities, workforce heterogeneity is optimal. These results do not rely on the restrictions on the way uncertainty is modeled or on the feasible set of agent types: they can be explained in terms of correlation between errors committed by different agents.

Transparency and deliberation within the FOMC: a computational linguistics approach

How does transparency, a key feature of central bank design, aect the deliberation of monetary policymakers? We exploit a natural experiment in the Federal Open Market Committee in 1993 together with computational linguistic models (particularly Latent Dirichlet Allocation) to measure the eect of increased transparency on debate. Commentators have hypothesized both a benecial discipline eect

Communication and influence

We study the information flows that arise among a set of agents with local knowledge and directed payoff interactions, which differ among pairs of agents. First, we study the equilibrium of a game where, before making decisions, agents can invest in pairwise active communication (speaking) and pairwise passive communication (listening). This leads to a full characterization of information and influence flows. Second, we show that, when the coordination motive dominates the adaptation motive, the influence of an agent on all his peers is approximately proportional to his eigenvector centrality. Third, we use our results to explain organizational phenomena such as: the emergence of work cliques; the adoption of human resources practices that foster communication (especially active communication); and the discrepancy between formal hierarchy and actual influence.

Organizational Economics with Cognitive Costs

Organizational economics has advanced along two parallel tracks, one concerned with motivating agents with diverging objectives, the other--less developed--with coordinating agents under cognitive limits. This survey focuses on the second strand and attempts to bring the two strands together. Organizations are viewed as responses to the cognitive costs faced by their (potential) members. We review existing approaches such as team theory, hierarchies of processors, organizational languages and knowledge hierarchies and we argue that they can help us address an array of important organizational issues. We also review recent developments in the application of these ideas: exploiting complexity measures, combining team theory and contract theory, applying organization theories in labor economics, and using these theories to interpret the wealth of activity data that is becoming available.