Paper # Author Title
We develop a dynamic model of opinion formation in social networks when the information required for learning a payoff-relevant parameter may not be at the disposal of any single agent. Individuals engage in communication with their neighbors in order to learn from their experiences. However, instead of incorporating the views of their neighbors in a fully Bayesian manner, agents use a simple updating rule which linearly combines their personal experience and the views of their neighbors (even though the neighbors’ views may be quite inaccurate). This non-Bayesian learning rule is motivated by the formidable complexity required to fully implement Bayesian updating in networks. We show that, as long as individuals take their personal signals into account in a Bayesian way, repeated interactions lead them to successfully aggregate information and learn the true underlying state of the world. This result holds in spite of the apparent na¨ıvet´e of agents’ updating rule, the agents’ need for information from sources the existence of which they may not be aware of, the possibility that the most persuasive agents in the network are precisely those least informed and with worst prior views, and the assumption that no agent can tell whether her own views or those of her neighbors are more accurate. Download Paper
Conditional cash transfer (CCT) programs have spread worldwide as a new form of social assistance for the poor. Previous evaluations of CCT programs focus mainly on rural settings, and little is known about their effects in urban areas. This paper studies the short-term (one and two-year) effects of the Mexican Oportunidades CCT program on urban children/youth. The program provides financial incentives for children/youth to attend school and for family members to visit health clinics. To participate, families had to sign up for the program and be deemed eligible. Difference-in-difference propensity score matching estimates indicate that the program is successful in increasing school enrollment, schooling attainment and time devoted to homework and in decreasing working rates of boys. Download Paper
We study the optimal provision of unemployment insurance (UI) over the business cycle. We use an equilibrium search and matching model with aggregate shocks to labor productivity, incorporating risk-averse workers, endogenous worker search effort decisions, and unemployment benefit expiration. We characterize the optimal UI policy, allowing both the benefit level and benefit duration to depend on the history of past aggregate shocks. We find that the optimal benefit is decreasing in current productivity and decreasing in current unemployment. Following a drop in productivity, benefits initially rise in order to provide short-run relief to the unemployed and stabilize wages, but then fall significantly below their pre-recession level, in order to speed up the subsequent recovery. Under the optimal policy, the path of benefits is pro-cyclical overall. As compared to the existing US UI system, the optimal history-dependent benefits smooth cyclical fluctuations in unemployment and deliver substantial welfare gains. Download Paper
We study the effects of changes in uncertainty about future fiscal policy on aggregate economic activity. Fiscal deficits and public debt have risen sharply in the wake of the financial crisis. While these developments make fisscal consolidation inevitable, there is considerable uncertainty about the policy mix and timing of such budgetary adjustment. To evaluate the consequences of this increased uncertainty, we first estimate tax and spending processes for the U.S. that allow for time-varying volatility. We then feed these processes into an otherwise standard New Keynesian business cycle model calibrated to the U.S. economy. We find that fiscal volatility shocks have an adverse effect on economic activity that is comparable to the effects of a 25-basis-point innovation in the federal funds rate. Download Paper
This paper studies the interaction between coordination and social learning in a dynamic regime change game. Social learning provides public information to which players overreact due to the coordination motive. So coordination affects the aggregation of private signals through players' optimal choices. Such endogenous provision of public information results in inefficient herds with positive probability, even though private signals have an unbounded likelihood ratio property. Therefore, social learning is a source of coordination failure. An extension shows that if players could individually learn, inefficient herding disappears, and thus coordination is successful almost surely. This paper also demonstrates that along the same history, the belief convergence differs in different equilibria. Finally, social learning can lead to higher social welfare when the fundamentals are bad. Download Paper
This paper analyzes the theoretical foundations of Giffen goods and details the difficulty with which prior studies have encountered limited empirical proof of Giffenity. Subsequently, a discussion of the economic overview of Russia during the early 1990s is provided. The paper then applies Giffenity to the newly established free market system of post-Soviet Union Russia while acknowledging changes in the prices for goods, specifically, for inferior food commodities. The paper concludes by advocating for the need to incorporate Giffenity into current economic theory to make it more comprehensive. Download Paper
This paper analyzes the causes and implications of recent financial crises. Financial crises in general lead to changes in both theory and practice of economics. The paper takes an historical overview. The global consensus of economic theory during the 20th century is discussed. The paper describes the Bretton Woods regime after World War II, details the era of adaptive expectations and motivates the emerging of the rational expectations school of thoughts. Various perspectives on the causes of the financial crisis are incorporated. The paper provides some policy suggestions and remarks on the consequences of ever-changing capital markets. Download Paper
Theoretical formulations of dynamic heterogeneous-agent economiestypically include a distribution as an aggregate state variable. This paperintroduces a method for computing equilibrium of these models by including a distribution directly as a state variable if it is finite-dimensional or a fine approximation of it if infinite-dimensional. The method accurately computes equilibrium in an extreme calibration of Huffman's (1987) overlapping-generations economy where quasi-aggregation, the accurate forecasting of prices using a small state space, fails to obtain. The method also accurately solves for equilibrium in a version of Krusell and Smith's (1998) economy wherein quasi-aggregation obtains but households face occasionally binding constraints. The method is demonstrated to be not only accurate but also feasible with equilibria for both economies being computed in under ten minutes in Matlab. Feasibility is achieved by using Smolyak's (1963) sparse-grid interpolation algorithm to limit the necessary number of gridpoints by many orders of magnitude relative to linear interpolation. Accuracy is achieved by using Smolyak's algorithm, which relies on smoothness, only for representing the distribution and not for other state variables such as individual asset holdings. Download Paper
This paper examines the where, when and why of first round entrepreneurial investment activity in the United States from the first quarter of 1995 until the second quarter of 2010. The paper analyzes these venture capital investments taking into consideration the role of macroeconomic variables, region, and industry. Additionally, trends in regional and industrial investments are evaluated using statistical and graphical analyses. By studying these findings, we are able to understand the impact of different periods of economic growth on venture capital investments. Lastly, the shock of the dot.com bubble and recent financial crisis are integrated into the findings. Download Paper
This paper concerns multistage games, with and without discounting, in which each player can increase the level of an action over time so as to increase the other players’ future payoffs. An action profile is achievable if it is the limit point of a subgame perfect equilibrium path. Necessary conditions are derived for achievability under relatively general conditions. They imply that any efficient profile that is approximately achievable must be in the core of the underlying coalitional game. In some but not all games with discounting, the necessary conditions for achievability are also sufficient for a profile to be the limit of achievable profiles as the period length shrinks to zero. Consequently, in these games when the period length is very short, (i) the set of achievable profiles does not depend on the move structure; (ii) an efficient profile can be approximately achieved if and only if it is in the core; and (iii) any achievable profile can be achieved almost instantly. Download Paper
Bankruptcy laws govern consumer default on unsecured credit. Foreclosure laws regulate default on secured mortgage debt. I investigate to what extent differences in foreclosure and bankruptcy laws can jointly explain variation in default rates across states. I construct a general equilibrium model where heterogeneous infinitely-lived households have access to unsecured borrowing and can finance housing purchases with mortgages. Households can default separately on both types of debt. The model is calibrated to match national foreclosure and bankruptcy rates and aggregate statistics related to household net worth and debt. The model can account for 83% of the variation in bankruptcy rates due to differences in bankruptcy and foreclosure law. I find that more generous homestead exemptions raise the cost of unsecured borrowing. Households in states with high exemptions therefore hold less unsecured and more mortgage debt compared to low exemption states, which leads to lower bankruptcy rates but higher foreclosure rates. The model also predicts recourse results in higher bankruptcy rates and a higher coincidence of foreclosure and bankruptcy. I use the model to evaluate how proposed and implemented changes to bankruptcy policy affect default rates and welfare. The 2005 Bankruptcy Abuse Prevention and Consumer Protection Act yields large welfare gains (1% consumption equivalent variation) but results in increases in both foreclosure and bankruptcy rates. I find that implementing the optimal joint foreclosure and bankruptcy policy, which is characterized by no-recourse mortgages and a homestead exemption equal to one quarter of median income, yields modest welfare gains (0.3% consumption equivalent variation). Download Paper
I structurally estimate an incomplete markets lifecycle model with endogenous labor supply, using data on the joint distribution of wages, hours and consumption. The model is successful at matching the evolution of both the first and second moments of the data over the lifecycle. The key challenge for the model is to generate declining inequality in annual hours worked over the first half of the working life, while respecting the constraints imposed by the data on consumption and wages. I argue that this is a robust feature of the data on lifecycle labor supply that is strongly at odds with the intra-temporal first order condition for labor supply. Allowing for a realistic degree of involuntary unemployment, coupled with preferences that feature nonseparability in the disutility of the extensive and intensive margins of hours worked, allows the model to overcome this challenge. The results imply that labor market frictions are important in jointly accounting for observed cross-sectional inequality in labor supply and consumption and may have quantitative relevance for analyses that exploit the intra-temporal first-order condition for labor. Download Paper
Many studies document significantly positive associations between schooling attainment and wages in developing countries. But when individuals enter occupations subsequent to completing their schooling, they not only face an expected work-life path of wages, but a number of other occupational characteristics, including wage risks and disability risks, for which there may be compensating wage differentials. This study examines the relations between schooling on one hand and mean wages and these two types of risks on the other hand, based on 77,685 individuals from the wage-earning population as recorded in six Labor Force Surveys of Pakistan. The results suggest that schooling is positively associated with mean total wages and wage rates, but has different associations with these two types of risks: Disability risks decline as schooling increases but wage risks, and even more, wage rate risks increase as schooling increases. The schooling-wage risks relation, but not the schooling-disability risks relation, is consistent with there being compensating differentials. Download Paper
Consider two agents who learn the value of an unknown parameter by observing a sequence of private signals. Will the agents commonly learn the value of the parameter, i.e., will the true value of the parameter become approximate common-knowledge? If the signals are independent and identically distributed across time (but not necessarily across agents), the answer is yes (Cripps, Ely, Mailath, and Samuelson, 2008). This paper explores the implications of allowing the signals to be dependent over time. We present a counterexample showing that even extremely simple time dependence can preclude common learning, and present sufficient conditions for common learning. Download Paper
Spain has experienced many financial crises through its history.  These financial crises have varied origins.  However, they do have common threads.  The current recession and subsequent debt crisis follow the same pattern.  The fiscal and monetary policies of the Spanish government have played a role in creating and prolonging the boom and bust cycles.  Government spending, government regulation, credit institutions, budget deficits, the political climate, and international trade are discussed to illuminate the causes and effects of these business cycles.  The Spanish government can take action to improve the economy and to lessen the effects of its financial crises. Download Paper
We study the optimal provision of unemployment insurance (UI) over the business cycle. We consider an equilibrium Mortensen-Pissarides search and matching model with risk-averse workers and aggregate shocks to labor productivity. Both the vacancy creation decisions of firms and the search effort decisions of workers respond endogenously to aggregate shocks as well as to changes in UI policy. We characterize the optimal history-dependent UI policy. We find that, all else equal, the optimal benefit is decreasing in current productivity and decreasing in current unemployment.  Optimal benefits are therefore lowest when current productivity is high and current unemployment is high. The optimal path of benefits reacts non-monotonically to a productivity shock. Following a drop in productivity, benefits initially rise in order to provide short-run relief to the unemployed and stabilize wages, but then fall significantly below their pre-recession level, in order to speed up the subsequent recovery. Under the optimal policy, the path of benefits is pro-cyclical overall. As compared to the existing US UI system, the optimal history-dependent benefits smooth cyclical fluctuations in unemployment and deliver non-negligible welfare gains. Download Paper
Dispersion of money balances among individuals is the basis for a range of policies but it has been abstracted from in monetary theory for tractability reasons. In this paper, we fill in this gap by constructing a tractable search model of money with a non-degenerate distribution of money holdings. We assume search to be directed in the sense that buyers know the terms of trade before visiting particular sellers. Directed search makes the monetary steady state block recursive in the sense that individuals’ policy functions, value functions and the market tightness function are all independent of the distribution of individuals over money balances, although the distribution affects the aggregate activity by itself. Block recursivity enables us to characterize the equilibrium analytically. By adapting lattice-theoretic techniques, we characterize individuals’ policy and value functions, and show that these functions satisfy the standard conditions of optimization. We prove that a unique monetary steady state exists. Moreover, we provide conditions under which the steady-state distribution of buyers over money balances is non-degenerate and analyze the properties of this distribution. Download Paper
Stochastic sequential bargaining models (Merlo and Wilson (1995, 1998)) have found wide applications in different fields including political economy and macroeconomics due to their flexibility in explaining delays in reaching an agreement. This paper presents new results in nonparametric identification and estimation of such models under different data scenarios. Download Paper
We propose and empirically implement a test for the presence of racial prejudice among emergency department (ED) physicians based on the bounceback rates of the patients who were discharged after receiving diagnostic tests during their initial ED visits. A bounceback is defined as a return to the ED within 72 hours of being initially discharged. Based on a plausible model of physician behavior, we show that differential bounceback rates across patients of different racial groups who are discharged after receiving diagnostic tests from their ED visits are informative of the racial prejudice of the physicians.  Applying the test to administrative data of ED visits from California and New Jersey, we do not find evidence of prejudice against black and Hispanic patients. Our finding suggests that, at least in the emergency department setting, taste based discrimination does not play an important role in the racial disparities in health care. Download Paper
The economic history of the United States is riddled with financial crises and banking panics.  During the nineteenth-century, eight major such episodes occurred.  In the period following World War II, some believed that these crises would no longer happen, and that the U.S. had reached a time of everlasting financial stability and sustainable growth.  The Savings and Loans Crisis of the 1980s, the 2001 dot-com bust and the 2007 housing bubble that led to the current global financial crises demonstrate that these phenomena are still reoccurring.  Regulators and policy makers should keep aware of the recurrence of such crises. Download Paper
This paper examines how beliefs about own HIV status affect decisions to engage in risky sexual behavior (as measured by extramarital affairs) and analyzes the potential for interventions that influence beliefs, such as HIV testing and informational campaigns, to reduce transmission rates. The empirical analysis is based on a panel survey of married males for years 2006 and 2008 from the Malawi Diffusion and Ideational Change Project (MDICP). In the data, beliefs about HIV status vary significantly geographically and over time, in part because of newly available testing opportunities and because of cultural differences. We estimate the effect of beliefs on risky behavior using Arellano and Carrasco’s (2003) semiparametric panel data estimator, which accommodates unobserved heterogeneity and belief endogeneity. Results show that changes in the belief of being HIV positive induce changes in risky behavior.Downward revisions in beliefs increase risky behavior and upward revisions decrease it. We modify Arellano and Carrasco’s (2003) estimator to allow for underreporting of extramarital affairs and find the estimates to be robust. Using the estimates and a prototypical epidemiological model of disease transmission, we show that better informing people about their HIV status on net reduces the population HIV transmission rate. Download Paper
We propose a model of history-dependent risk attitude (HDRA), allowing the attitude of a decision-maker (DM) towards risk at each stage of a T-stage lottery to evolve as a function of his history of disappointments and elations in prior stages. We establish an equivalence between the existence of an HDRA representation and two documented cognitive biases. First, the DM’s risk attitudes are reinforced by prior experiences: he becomes more risk averse after suffering a disappointment and less risk averse after being elated. Second, the DM displays a primacy effect: early outcomes have the strongest effect on risk attitude. Furthermore, the DM lowers his threshold for elation after a disappointing outcome and raises it after an elating outcome; this makes disappointment more likely after elation and vice-versa, leading to statistically reversing risk attitudes. “Gray areas” in the elation-disappointment assignment are connected to optimism and pessimism in determining endogenous reference points.  Download Paper
This paper studies the inference of interaction effects (impacts of players' actions on each other's payoffs) in discrete simultaneous games with incomplete information. We propose an easily implementable test for the signs of state-dependent interaction effects that does not require parametric specifications of players' payoffs, the distributions of their private signals or the equilibrium selection mechanism. The test relies on the commonly invoked assumption that players' private signals are independent conditional on observed states. The procedure is valid in (but does not rely on) the presence of multiple equilibria in the data-generating process (DGP). As a by-product, we propose a formal test for multiple equilibria in the DGP.  We also show how to extend our arguments to identify signs of interaction effects when private signals are correlated. We provide Monte Carlo evidence of the test's good performance in finite samples. We then implement the test using data on radio programming of commercial breaks in the U.S., and infer stations' incentives to synchronize their commercial breaks. Our results support the earlier finding by Sweeting (2009) that stations have stronger incentives. Download Paper
We study the recruitment of individuals in the political sector. We propose an equilibrium model of political recruitment by two political parties competing in an election. We show that political parties may deliberately choose to recruit only mediocre politicians, in spite of the fact that they could select better individuals.  Furthermore, we show that this phenomenon is more likely to occur in proportional than in majoritarian electoral systems Download Paper
This paper studies the nonparametric identification and estimation of voters' preferences when voters are ideological. We build on the methods introduced by Degan and Merlo (2009) representing elections as Voronoi tessellations of the ideological space. We exploit the properties of this geometric structure to establish that voter preference distributions and other parameters of interest can be identified from aggregate electoral data. We also show that these objects can be consistently estimated using the methodology proposed by Ai and Chen (2003) and we illustrate our analysis by performing an actual estimation using data from the 1999 European Parliament elections. Download Paper
What determines which assets are used in transactions? We develop a framework where the extent to which assets are recognizable determines the extent to which they are acceptable in exchange - i.e., their liquidity. We analyze the effects of monetary policy on asset markets. Recognizability and liquidity are endogenized by allowing agents to invest in information. There can be multiple equilibria with different transaction patterns. These transaction patterns are not invariant to policy. We show small changes in information that may generate large responses in prices, allocations and welfare. We also discuss issues in international economics, including exchange rates and dollarization. Download Paper
There is a large repeated games literature illustrating how future interactions provide incentives for cooperation. Much of this literature assumes public monitoring: players always observe precisely the same thing. Even slight deviations from public monitoring to private monitoring that incorporate differences in players’ observations dramatically complicate coordination. Equilibria with private monitoring often seem unrealistically complex. We set out a model in which players accomplish cooperation in an intuitively plausible fashion. Players process information via a mental system — a set of psychological states and a transition function between states depending on observations. Players restrict attention to a relatively small set of simple strategies, and consequently, might learn which perform well. Download Paper
Marcet and Marimon (1994, revised 1998) developed a recursive saddle point method which can be used to solve dynamic contracting problems that include participation, enforcement and incentive constraints. Their method uses a recursive multiplier to capture implicit prior promises to the agent(s) that were made in order to satisfy earlier instances of these constraints. As a result, their method relies on the invertibility of the derivative of the Pareto frontier and cannot be applied to problems for which this frontier is not strictly concave. In this paper we show how one can extend their method to a weakly concave Pareto frontier by expanding the state space to include the realizations of an end of period lottery over the extreme points of a .at region of the Pareto frontier. With this expansion the basic insight of Marcet and Marimon goes through .one can make the problem recursive in the Lagrangian multiplier which yields significant computational advantages over the conventional approach of using utility as the state variable. The case of a weakly concave Pareto frontier arises naturally in applications where the principal’s choice set is not convex but where randomization is possible. Download Paper
Different markets are cleared by different types of prices---seller-specific prices that are uniform across buyers in some markets, and personalized prices tailored to the buyer in others. We examine a setting in which buyers and sellers make investments before matching in a competitive market. We introduce the notion of premuneration values---the values to the transacting agents prior to any transfers---created by a buyer-seller match. Personalized price equilibrium outcomes are independent of premuneration values and exhibit inefficiencies only in the event of "coordination failures," while uniform-price equilibria depend on premuneration values and in general feature inefficient investments even without coordination failures. There is thus a trade-off between the costs of personalizing prices and the inefficient investments under uniform prices. We characterize the premuneration values under which uniform-price equilibria similarly exhibit inefficiencies only in the event of coordination failures. Download Paper
This paper investigates the empirical importance of allowing for multi-dimensional sources of unobserved heterogeneity in auction models with private information. It in turn develops the estimation procedure that recovers the distribution of private information in the presence of two distinct sources of unobserved heterogeneity. It is shown that this estimation procedure identifies components of the model and produces uniformly consistent estimators of these components. The estimation procedure is applied to the data from highway procurement. The results of the estimation indicate that allowing for two-dimensional unobserved heterogeneity may significantly affect the results of estimation as well as policy-relevant instruments derived from the estimated distributions of bidders’ costs. Download Paper
We study how exploration versus exploitation innovations impact economic growth through a tractable endogenous growth framework that contains multiple innovation sizes, multi-product firms, and entry/exit. Firms invest in exploration R&D to acquire new product lines and exploitation R&D to improve their existing product lines. We model and show empirically that exploration R&D does not scale as strongly with firm size as exploitation R&D. The resulting framework conforms to many regularities regarding innovation and growth differences across the firm size distribution. We also incorporate patent citations into our theoretical framework. The framework generates a simple test using patent citations that indicates that entrants and small firms have relatively higher growth spillover effects. Download Paper
Why do some sellers set prices in nominal terms that do not respond to changes in the aggregate price level? In many models, prices are sticky by assumption. Here it is a result. We use search theory, with two consequences: prices are set in dollars since money is the medium of exchange; and equilibrium implies a nondegenerate price distribution. When money increases, some sellers keep prices constant, earning less per unit but making it up on volume, so profit is unaffected. The model is consistent with the micro data. But, in contrast with other sticky-price models, money is neutral Download Paper
We extend the semi-parametric estimation method for dynamic discrete choice models using Hotz and Miller’s (1993) conditional choice probability (CCP) approach to the setting where individuals may have hyperbolic discounting time preferences and may be naive about their time inconsistency. We illustrate the proposed estimation method with an empirical application of adult women’s decisions to undertake mammography to evaluate the importance of present bias and naivety in the under-utilization of this preventive health care. Our results show evidence for both present bias and naivety. Download Paper
This note provides several generalizations of Mailath's (1987) result that incentive compatibility plus separation implies differentiability. The new results extend the theory to classic models in finance such as Leland and Pyle (1977), Glosten (1989), and De Marzo and Duffie (1999), that were not previously covered. Download Paper
Social norms are often posited as an explanation of differences in economic behavior and performance of societies that are difficult to explain by differences in endowments and technology. Economists are often reluctant to incorporate social aspects into their analyses when doing so leads to models that depart from the “standard” model. I discuss ways that agents’ social environment can be accommodated in standard models and the advantages and disadvantages of doing so. Download Paper