Knowledge that Transforms

Consider an extensive‐form mechanism, run by an auctioneer who communicates sequentially and privately with bidders. Suppose the auctioneer can deviate from the rules provided that no single bidder detects the deviation. A mechanism is credible if it is incentive‐compatible for the auctioneer to follow the rules. We study the optimal auctions in which only winners pay, under symmetric independent private values. The first‐price auction is the unique credible static mechanism. The ascending auction is the unique credible strategy‐proof mechanism.

LET ME FIRST BRIEFLY RECALL the bias expressions in the paper.For simplicity, throughout I will fix a value η of the base model parameter.Let f η ζ be the density of the data D under the reader's model.Let f η denote the density of D under the base model.Given a quantity of interest c(η), the unrestricted bias of c is

This paper proposes a class of games called revision games . In a revision game, players start with initially prepared actions, followed by a sequence of random revision opportunities until a predetermined deadline. In the course of revisions, players monitor each other's behavior. It is shown that players can cooperate and that their behavior under the optimal equilibrium is described by a simple differential equation. We present the necessary and sufficient conditions for cooperation to be sustained in revision games. We also present applications to the preopening activities in the stock exchange and to an electoral campaign.

We study the role of financial frictions and firm heterogeneity in determining the investment channel of monetary policy. Empirically, we find that firms with low default risk—those with low debt burdens and high “distance to default”— are the most responsive to monetary shocks. We interpret these findings using a heterogeneous firm New Keynesian model with default risk. In our model, low‐risk firms are more responsive to monetary shocks because they face a flatter marginal cost curve for financing investment. The aggregate effect of monetary policy may therefore depend on the distribution of default risk, which varies over time.

This paper considers a Principal–Agent model with hidden action in which the Principal can monitor the Agent by acquiring independent signals conditional on effort at a constant marginal cost. The Principal aims to implement a target effort level at minimal cost. The main result of the paper is that the optimal information‐acquisition strategy is a two‐threshold policy and, consequently, the equilibrium contract specifies two possible wages for the Agent. This result provides a rationale for the frequently observed single‐bonus wage contracts .

Can digital information and communication technology foster mass political mobilization? We use a novel georeferenced data set for the entire African continent between 1998 and 2012 on the coverage of mobile phone signal together with georeferenced data from multiple sources on the occurrence of protests and on individual participation in protests to bring this argument to empirical scrutiny. We find that while mobile phones are instrumental to mass mobilization, this only happens during economic downturns, when reasons for grievance emerge and the cost of participation falls. The results are in line with insights from a network model with imperfect information and strategic complementarities in protest occurrence. Mobile phones make individuals more responsive to both changes in economic conditions—a mechanism that we ascribe to enhanced information —and to their neighbors' participation—a mechanism that we ascribe to enhanced coordination .

We introduce a new family of dynamic mechanisms that restricts sellers from using future distributional knowledge. Since the allocation and pricing of each auction period do not depend on the type distributions of future periods, we call this family of dynamic mechanisms non‐clairvoyant. We develop a framework (bank account mechanisms) for characterizing, designing, and proving lower bounds for dynamic mechanisms (clairvoyant or non‐clairvoyant). We use the same methods to compare the revenue extraction power of clairvoyant and non‐clairvoyant dynamic mechanisms.

This paper considers a class of generalized methods of moments (GMM) estimators for general dynamic panel models, allowing for weakly exogenous covariates and cross‐sectional dependence due to spatial lags, unspecified common shocks, and time‐varying interactive effects. We significantly expand the scope of the existing literature by allowing for endogenous time‐varying spatial weight matrices without imposing explicit structural assumptions on how the weights are formed. An important area of application is in social interaction and network models where our specification can accommodate data dependent network formation. We consider an exemplary social interaction model and show how identification of the interaction parameters is achieved through a combination of linear and quadratic moment conditions. For the general setup we develop an orthogonal forward differencing transformation to aid in the estimation of factor components while maintaining orthogonality of moment conditions. This is an important ingredient to a tractable asymptotic distribution of our estimators. In general, the asymptotic distribution of our estimators is found to be mixed normal due to random norming. However, the asymptotic distribution of our test statistics is still chi‐square.

Using an analytically tractable heterogeneous agent New Keynesian model, we show that whether incomplete markets resolve New Keynesian “paradoxes” depends on the cyclicality of income risk. Incomplete markets reduce the effectiveness of forward guidance and multipliers in a liquidity trap only with procyclical risk. Countercyclical risk amplifies these “puzzles.” Procyclical risk permits determinacy under a peg; countercyclical risk may generate indeterminacy even under the Taylor principle. By affecting the cyclicality of risk, even “passive” fiscal policy influences the effects of monetary policy.

We consider social welfare functions that satisfy Arrow's classic axioms of independence of irrelevant alternatives and Pareto optimality when the outcome space is the convex hull of some finite set of alternatives. Individual and collective preferences are assumed to be continuous and convex, which guarantees the existence of maximal elements and the consistency of choice functions that return these elements, even without insisting on transitivity. We provide characterizations of both the domains of preferences and the social welfare functions that allow for anonymous Arrovian aggregation. The domains admit arbitrary preferences over alternatives, which completely determine an agent's preferences over all mixed outcomes. On these domains, Arrow's impossibility turns into a complete characterization of a unique social welfare function, which can be readily applied in settings involving divisible resources such as probability, time, or money.