Paper # Author Title
This paper studies the nonparametric identification and estimation of voters’ preferences when voters are ideological. We 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 and illustrate our analysis by performing an actual estimation using data from the 1999 European Parliament elections. Download Paper
This paper examines how beliefs about own HIV status aect decisions to engage in risky sexual behavior, as measured by having extramarital sex and/or multiple sex partners. The empirical analysis is based on a panel survey of males from the 2006 and 2008 rounds of the Malawi Diusion and Ideational Change Project (MDICP). The paper first develops a behavioral model of the belief-risky behavior relationship. It then estimates the causal effect of beliefs on risky behavior in a way that takes into account the belief updating mechanisms implied by the model. In particular, the Arellano and Carrasco (2003) semiparametric panel data estimator that is used accommodates both unobserved heterogeneity and belief endogeneity, arising from dependence of current beliefs on past risky behavior. Results show that downward revisions in the belief assigned to being HIV positive increase risky behavior and upward revisions decrease it. We estimate for example that a change in the perceived probability of being HIV positive from 0 to 100% reduces risky behavior between 13.7 and 36.4 percentage points depending on the risky behavior definition and year. Implementation of a modied estimator that allows for misreporting of risky behavior finds the estimates to be downward biased but relatively robust to a wide range of plausible misreporting levels. 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
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
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
We test implications of a simple equilibrium model of informality using a survey of 48,000+ small firms in Brazil. In the model, agent's ability to manage production differ and informal firms face a higher cost of capital and limitation on size, although these informal firms avoid tax payments. As a result, informal firms are managed by less able entrepreneurs, are smaller, and employ a lower capital-labor ratio. The model predicts that the interaction of an index of observable inputs to entrepreneurial ability and formality is positively correlated with firm size, which we verify in the data. Using the model, we estimate that informal firms in our dataset faced at least 1.3 times the cost of capital of formal firms. Download Paper
This paper examines how beliefs about own HIV status affect decisions to engage in risky sexual behavior using data on married males living in Malawi. Risky behavior is measured as the propensity to engage in extramarital affairs. The empirical analysis is based on panel surveys for years 2006 and 2008 from the Malawi Diffusion and Ideational Change Project (MDICP). Beliefs vary significantly over time in the data, in part because of HIV testing and informational campaigns. We estimate the effect of beliefs about own HIV status on risky behavior using a panel data estimator developed by Arellano and Carrasco (2003), which accommodates unobserved heterogeneity as well as belief endogeneity arising from the dependence of current beliefs on lagged behaviors. We find that beliefs are an important determinant of risky behavior, with downward revisions in the belief of being HIV positive increasing risky behavior and upward revisions decreasing it. We modify Arellano and Carrasco’s (2003) estimator to allow for underreporting of affairs and find the estimates to be relatively robust to underreporting. Using our estimates and a prototypical epidemiological model of disease transmission, we show that making individuals better informed about their HIV status, either by increasing the credibility of test results and/or increasing access to testing, would on net reduce the HIV transmission rate. Download Paper
This paper studies the inference of interaction effects, i.e., the 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 the presence of multiple equilibria, and, as a by-product of our approach, we propose a formal test for multiple equilibria in the data-generating process.  We provide Monte Carlo evidence of the test's good performance infinite samples. We also implement the test to infer the direction of interaction effects in couples' joint retirement decisions using data from the Health and Retirement Study. Download Paper
This paper studies the inference of interaction effects, i.e., the 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 the presence of multiple equilibria, and, as a by-product of our approach, we propose a formal test for multiple equilibria in the data-generating process.  We provide Monte Carlo evidence of the test's good performance in finite samples. We also implement the test to infer the direction of interaction effects in couples' joint retirement decisions using data from the Health and Retirement Study. Download Paper
This paper examines whether and to what extent changes in beliefs about own HIV status induce changes in risky sexual behavior using data from married males living in three regions of Malawi. Risky behavior is measured as the propensity to engage in extramarital affairs. The empirical analysis is based on panel surveys for years 2006 and 2008 from the Malawi Diffusion and Ideational Change Project (MDICP), which contain detailed information on beliefs about HIV status and on sexual behaviors. Many individuals change their beliefs over time, because of opportunities to get tested for HIV and informational campaigns. We estimate the effect of belief revisions on the propensity to engage in extra-marital affairs using a panel data estimator developed by Arellano and Carrasco (2003), which accommodates unobserved heterogeneity as well as belief endogeneity arising from the dependence of current beliefs on lagged behaviors. We find that downward revisions in the belief of being HIV positive lead to an increased propensity to engage in extra-marital affairs and upward revisions to a decreased propensity. The estimates are shown to be robust to underreporting of affairs. Using our estimates and a standard epidemeological model of disease transmission, we find that increasing the responsiveness of beliefs to test results would reduce the HIV transmission rate as infected individuals reduce sexual behavior and decrease the likelihood that uninfected persons have contact with an HV-positive person. Download Paper
We test implications of a simple equilibrium model of informality using a survey of 48,000+ small firms in Brazil. In the model, agent's ability to manage production differ and informal firms face a higher cost of capital and limitation on size, although these informal firms avoid tax payments. As a result, informal firms are managed by less able entrepreneurs, are smaller and employ a lower capital-labor ratio. When education is an imperfect proxy for ability, the model predicts that the interaction of the manager's education and formality is positively correlated with firm size. Using the model, we estimate that informal firms in our dataset faced at least 1.3 times the cost of capital Download Paper
This paper investigates determinants of informal economic activity. We present an equilibrium model of informality and test its implications using a survey of 48,000+ small firms in Brazil. We define informality as tax avoidance; firms in the informal sector avoid tax payments but suffer other limitations. A novel theoretical contribution in this model is the role of value added taxes in transmitting informality. It predicts that the informality of a firm is correlated to the informality of firms from which it buys or sells. The model also implies that higher tolerance for informal firms in one production stage increases tax avoidance in downstream and upstream stages. Empirical analysis shows that, in fact, various measures of formality of suppliers and purchasers (and its enforcement) are correlated with the formality of a firm. Even more interestingly, when we look at sectors where Brazilian firms are not subject to the credit system of value added tax, but instead the value added tax is applied at some stage of production at a rate that is estimated by the tax authorities, this chain effect vanishes. Download Paper
This paper studies the identification of a simultaneous equation model involving duration measures.  It proposes a game theoretic model in which durations are determined by strategic agents. In the absence of strategic motives, the model delivers a version of the generalized accelerated failure time model. In its most general form, the system resembles a classical simultaneous equation model in which endogenous variables interact with observable and unobservable exogenous components to characterize an economic environment. In this paper, the endogenous variables are the individually chosen equilibrium durations. Even though a unique solution to the game is not always attainable in this context, the structural elements of the economic system are shown to be semiparametrically identified. We also present a brief discussion of estimation ideas and a set of simulation studies on the model. Download Paper
This paper examines whether and to what extent changes in beliefs about own HIV status induce changes in risky sexual behavior using data from married males living in three regions of Malawi. Risky behavior is measured as the propensity to engage in extramarital affairs. The empirical analysis is based on panel surveys for years 2006 and 2008 from the Malawi Diffusion and Ideational Change Project (MDICP), which contain detailed information on beliefs about HIV status and on sexual behaviors. Many individuals change their beliefs over time, in part because of opportunities to get tested for HIV and informational campaigns. We estimate the effect of belief revisions on the propensity to engage in extra-marital affairs using a panel data estimator developed by Arellano and Carrasco (2003). The estimator accommodates unobserved heterogeneity as well as belief endogeneity arising from the dependence of current beliefs on lagged behaviors. We find that downward revisions in the belief of being HIV positive lead to an increased propensity to engage in extra-marital affairs and upward revisions to a decreased propensity. The estimates are shown to be robust to underreporting of affairs. Download Paper
This paper investigates determinants of informal economic activity. We present an equilibrium model of informality and test its implications using a survey of 48,000+ small firms in Brazil. We define informality as tax avoidance; firms in the informal sector avoid tax payments but suffer other limitations. A novel theoretical contribution in this model is the role of value added taxes in transmitting informality. It predicts that the informality of a firm is correlated to the informality of firms from which it buys or sells. The model also implies that higher tolerance for informal firms in one production stage increases tax avoidance in downstream and upstream stages. Empirical analysis shows that, in fact, various measures of formality of suppliers and purchasers (and its enforcement) are correlated with the formality of a firm. Even more interestingly, when we look at sectors where Brazilian firms are not subject to the credit system of value added tax, but instead the value added tax is applied at some stage of production at a rate that is estimated by the tax authorities, this chain effect vanishes. Download Paper
This paper studies the identification of a simultaneous equation model involving duration measures. It proposes a game theoretic model in which durations are determined by strategic agents. In the absence of strategic motives, the model delivers a version of the generalized accelerated failure time model. In its most general form, the system resembles a classical simultaneous equation model in which endogenous variables interact with observable and unobservable exogenous components to characterize a certain economic environment. In this paper, the endogenous variables are the individually chosen equilibrium durations. Even though a unique solution to the game is not always attainable in this context, the structural elements of the economic system are shown to be semiparametrically point identified. We also present a brief discussion of estimation ideas and a set of simulation studies on the model. Download Paper
This paper examines how beliefs about own HIV status affect sexual behavior. Risky behavior is measured as the propensity to engage in extramarital affairs or not use condoms. The empirical analysis is based on 2004 and 2006 data from the Malawi Diffusion and Ideational Change Project. Controlling for endogeneity between beliefs and risk-taking, we find that downward revisions in the belief of being HIV positive lead to a lower propensity to engage in extramarital affairs but have no effect on condom use. We show that the estimates provide a lower bound when there is measurement error in reported extra-marital affairs. Download Paper
Many HIV testing programs in Africa and elsewhere aim to reduce risk-taking behaviors by providing individuals with information about their own HIV status. This paper examines how beliefs about own HIV status affect risky sexual behavior using data from married couples living in three regions of Malawi. Risky behavior is measured as the propensity to engage in extramarital affairs or to not use condoms. The empirical analysis is based on two panel surveys for years 2004 and 2006 from the Malawi Diffusion and Ideational Change Project (MDICP) and from an experimental HIV testing intervention carried out in 2004 that provided randomized incentives for picking up test results. Most individuals participating in the MDICP testing learned that they were HIV negative and a small fraction that they were positive. Controlling for potential endogeneity between beliefs and risk-taking, we find that downward revisions in the subjective belief of being HIV positive lead to decreases in the propensity to engage in extra-marital affairs but have no effect on condom use. These results are generally supported by survey questions that directly elicited from respondents how participating in testing altered their behavior. We show that the estimates provide a lower bound in the presence of measurement error in extra-marital affairs. Download Paper
This paper studies inference in a continuous time game where an agent's decision to quit an activity depends on the participation of other players. In equilibrium, similar actions can be explained not only by direct influences but also by correlated factors. Our model can be seen as a simultaneous duration model with multiple decision makers and interdependent durations. We study the problem of determining the existence and uniqueness of equilibrium stopping strategies in this setting. This paper provides results and conditions for the detection of these endogenous effects. First, we show that the presence of such effects is a necessary and sufficient condition for simultaneous exits. This allows us to set up a nonparametric test for the presence of such influences which is robust to multiple equilibria. Second, we provide conditions under which parameters in the game are identified. Finally, we apply the model to data on desertion in the Union Army during the American Civil War and find evidence of endogenous influences. Download Paper
This paper investigates the determinants of informal economic activity. We present two equilibrium models of informality and test their implications using a survey of 48,000+ small firms in Brazil. We define informality as tax avoidance; firms in the informal sector avoid tax payments but suffer other limitations. In the first model there is a single industry and informal firms face a higher cost of capital and a limitation on size. As a result informal firms are smaller and have a lower capital-labor ratio. When education is an imperfect proxy for ability, we show that the interaction of the manager's education and formality has a positive correlation with firm size. These implications are supported by our empirical analysis. A novel theoretical contribution in this paper is a model that highlights the role of value added taxes in transmitting informality. It predicts that the informality of a firm is correlated to the informality of firms from which it buys or sells. The model also implies that higher tolerance for informal firms in one production stage increases tax avoidance in downstream and upstream sectors. Empirical analysis shows that, in fact, various measures of formality of suppliers and purchasers (and its enforcement) are correlated with the formality of a firm. Even more interestingly, when we look at sectors where Brazilian firms are not subject to the credit system of value added tax, but instead the value added tax is applied at some stage of production at a rate that is estimated by the State, this chain effect vanishes. Download Paper
Consider two random variables X and Y . In initial probability and statistics courses, a discussion of various concepts of dissociation between X and Y is customary. These concepts typically involve independence and uncorrelatedness. An example is shown where E(Y^n|X) = E(Y^n) and E(X^n|Y) = E(X^n)  for n = 1, 2,… and yet X and Y are not stochastically independent. The bi-variate distribution is constructed using a well-known example in which the distribution of a random variable is not uniquely determined by its sequence of moments. Other similar families of distributions with identical moments can be used to display such a pair of random variables. It is interesting to note in class that even such a degree of dissociation between the moments of X and Y does not imply stochastic independence. and yet X and Y are not stochastically independent. The bi-variate distribution is constructed using a well-known example in which the distribution of a random variable is not uniquely determined by its sequence of moments. Other similar families of distributions with identical moments can be used to display such a pair of random variables. It is interesting to note in class that even such a degree of dissociation between the moments of X and Y does not imply stochastic independence. Download Paper
This paper studies the identification of a simultaneous equation model where the variable of interest is a duration measure. It proposes a game theoretic model in which durations are determined by strategic agents. In the absence of strategic motives, the model delivers a version of the generalized accelerated failure time model. In its most general form, the system resembles a classical simultaneous equation model in which endogenous variables interact with observable and unobservable exogenous components to characterize a certain economic environment. In this paper, the endogenous variables are the individually chosen equilibrium durations. Even though a unique solution to the game is not always attainable in this context, the structural elements of the economic system are shown to be semiparametrically point identified. We also present a brief discussion of estimation ideas and a set of simulation studies on the model. Download Paper
This paper investigates the determinants of informal economic activity. We present two equilibrium models of informality and test their implications using a survey of 48,000+ small firms in Brazil. We define informality as tax avoidance; firms in the informal sector avoid tax payments but suffer other limitations. In the first model there is a single industry and informal firms face a higher cost of capital and a limitation on size. As a result informal firms are smaller and have a lower capital-labor ratio. When education is an imperfect proxy for ability, we show that the interaction of the manager’s education and formality has a positive correlation with firm size. These implications are supported by our empirical analysis. A novel theoretical contribution in this paper is a model that highlights the role of value added taxes in transmitting informality. It predicts that the informality of a firm is correlated to the informality of firms from which it buys or sells. The model also implies that higher tolerance for informal firms in one production stage increases tax avoidance in downstream and upstream sectors. Empirical analysis shows that, in fact, various measures of formality of suppliers and purchasers (and its enforcement) are correlated with the formality of a firm. Even more interestingly, when we look at sectors where Brazilian firms are not subject to the credit system of value added tax, but instead the value added tax is applied at some stage of production at a rate that is estimated by the State, this chain effect vanishes. Download Paper
This paper investigates the determinants of informal economic activity. We present two equilibrium models of informality and test their implications using a survey of 48,000+ small firms in Brazil. We define informality as tax avoidance; firms in the informal sector avoid tax payments but suffer other limitations. In the first model there is a single industry and informal firms face a higher cost of capital and a limitation on size. As a result informal firms are smaller and have a lower capital labor ratio. When education is an imperfect proxy for ability, we show that the interaction of the manager’s education and formality has a positive correlation with firm size. These implications are supported by our empirical analysis. A novel theoretical contribution in this paper is a model that highlights the role of value added taxes in transmitting informality. It predicts that the informality of a firm is correlated to the informality of firms from which it buys or sells. The model also implies that higher tolerance for informal firms in one production stage increases tax avoidance in downstream and upstream sectors. Empirical analysis shows that, in fact, various measures of formality of suppliers and purchasers (and its enforcement) are correlated with the formality of a firm. Even more interestingly, when we look at sectors where Brazilian firms are not subject to the credit system of value added tax, but instead the value added tax is applied at some stage of production at a rate that is estimated by the State, this chain effect vanishes. Download Paper
This paper studies inference in a continuous-time game where an agent’s decision to quit an activity depends on the participation of other players. In equilibrium, similar actions can be explained not only by direct influences, but also by correlated factors. Our model can be seen as a simultaneous duration model with multiple decision makers and interdependent durations. We study the problem of determining existence and uniqueness of equilibrium stopping strategies in this setting. This paper provides results and conditions for the detection of these endogenous effects. First, we show that the presence of such effects is a necessary and sufficient condition for simultaneous exits. This allows us to set up a nonparametric test for the presence of such influences which is robust to multiple equilibria. Second, we provide conditions under which parameters in the game are identified. Finally, we apply the model to data on desertion in the Union Army during the American Civil War and find evidence of endogenous influences. Download Paper