Collision and Collusion


Book Description

The present dissertation consists of three essays on Econometrics of discrete outcome models. The first essay analyses possibility of discriminating between several solution concepts in a general class of semiparametric finite games with complete information based on observed data on outcomes and characteristics of agents. I find conditions under which it is possible to identify whether actual behavior of agents is consistent with a given solution concept. I propose different applications for my general methodology. For example, I can identify whether and how often firms play Nash equilibria (NE) in an entry game, which equilibria are more likely to be selected, and whether profit functions are private information or common knowledge. I also identify whether choices are sequential or simultaneous. The second essay is a logical continuation of the first one. I focus on entry games with complete information and provide a statistical tool to test for the NE solution concept. I develop a sieve likelihood ratio type procedure to test whether the NE assumption can rationalize the data on outcomes and payoff shifters in semiparametric entry games with second-order rational firms. I allow agents to play mixed strategy NE in the regions of NE multiplicity. I do not impose parametric restrictions on the way firms randomize between different equilibria. The testing procedure does not assume that the model is point identified. I apply the proposed procedure to the data on entry and exit decisions of small grocery stores in rural areas in the USA. In the third essay I address the issue of data availability in parametric binary outcome models. In particular, I consider environments where the researcher only observes the data that correspond to a particular outcome (pure choice-based data) and has some auxiliary information about the distribution of the explanatory variables. I propose a Generalized Method of Moments type procedure to estimate parametric binary models with pure choice-based data when auxiliary information on distribution of explanatory variables is available. As an empirical application of my procedure, I estimate the probability of a two-car collision based on the data on all police reported accidents in Seattle from 2002-2011.







Essays on the Econometrics of Games


Book Description

This dissertation studies identification, estimation and inference for various types of staticgames of incomplete information, a class of games in which players do not have full information about their opponents. Such games have been widely used in the empirical studies of strategic interactions such as market entry, technology adoption and so on. Chapter 1 studies sequential estimation and uniform inference in a static game of incomplete information with nonseparable unobserved heterogeneity. We propose a novel methodfor sequentially estimating payoff function and conducting uniform inference in static games of incomplete information with non-separable unobserved heterogeneity (and multiple equilibria). We tackle the matching-types problem by constructing a new characterization of the payoff function via a minimum distance model with incorrect "moments." For several specifications of the payoff function, we propose to select the correct matching and estimate the payoff function jointly using a minimum distance type criterion function with a rewarding term when needed; we show consistency of the selected matching and the estimator of the payoff function; we construct an asymptotically uniformly valid and easy-to-implement test for the linear hypothesis on the payoff function; and for large state spaces, we introduce a sequential Monte Carlo method to ease computational burden. We report results from a small simulation study and an application to the dataset of Sweeting (2009). Chapter 2 proposes a simple estimator for static game of incomplete information with action complementarity. Oligopolists often engage in strategic interactions in multiple relatedbusinesses or industries. Such phenomenon could be analyzed using game theoretic models with action complementarity (substitutability). In this paper we study the semiparametric identification and estimation of static games of incomplete information with complementary (substitutable) actions. Building on and extending the identifiability result for bundled demand in Fox and Lazzati (2017), we show that structural parameters in this game are identified. A simple closed-form estimator for the structural parameters is proposed based on our identification strategy. The estimator could be implemented easily by running a three-stage least squares, and no numerical optimization is needed. We establish the root-n consistency and asymptotic normality of this estimator. A small Monte Carlo simulation shows the efficacy of our methods in finite samples. Chapter 3 studies identification and estimation of a binary game of incomplete information under symmetry of the unobservables. We study the semiparametric identificationand estimation of a class of binary game of incomplete information under the restriction of conditional symmetry for unobserved private information. We use a two-step identification strategy that is based on the equilibrium condition and the symmetry restriction. We propose a two-step minimum distance estimator, and prove its root-N consistency and asymptotic normality. Compared to existing semiparametric method in the literature, our estimator could adapt arbitrary forms of heteroskedasticity in common knowledge state variables and does not require stringent support and tail conditions. Our method could be extended to allow for multiple equilibria and symmetrically distributed random coefficients. A small Monte Carlo study demonstrates the efficacy and robustness of our estimator compared to the popular two-step pseudo maximum likelihood method.




Essays on Information Economics and Game Theory


Book Description

This dissertation has two chapters, one on information economics and one on game theory. The first chapter studies the scenarios where an analyst learns about a random variable by observing an ongoing rational experimentation. We assume an optimal stopping exercise with binary signals about a binary state of the world. The analyst observes a public history of experiments, but not an earlier experimentation pre-history of uncertain length. In this setting, a dynamic survivor bias emerges: the naive Bayes-updates ignoring the pre-history is more pessimistic than the sophisticated updates that accounts for all possible pre-histories consistent with an ongoing rational experimentation. We show that this bias is dynamic in the sense that the observation impacts the inference of the un-observed pre-history. In general, we find that the analyst's Bayes-optimal inference critically depends on the ordering of the signal history and the combined knowledge of the signal realizations and the experimenter's actions. My theory has implications for technology adoption in R & D settings, and formally subsumes a class of one armed bandits and the Wald experimentation problem, for instance. The second chapter studies a static population game with strategic substitutes. I assume one dimensional continuous action with heterogeneous action cost among players. I explore the diminishing cross effect condition on the payoff function, which delivers equilibrium uniqueness and several comparative statics results -- 1. The equilibrium distribution of actions level rises in the first order stochastic dominance order when the type distribution falls in the first order stochastic dominance order and the dispersion order. 2. The equilibrium distribution of actions rises when the own action effect is larger. My model has applications in games with a p2p network structure and other massive social interactions with a pairwise matching nature.




Identification and Estimation of Discrete Games of Complete Information


Book Description

We discuss the identification and estimation of discrete games of complete information. Following Bresnahan and Reiss (1990, 1991), a discrete game is a generalization of a standard discrete choice model where utility depends on the actions of other players. Using recent algorithms to compute all of the Nash equilibria to a game, we propose simulation-based estimators for static, discrete games. With appropriate exclusion restrictions about how covariates enter into payoffs and influence equilibrium selection, the model is identified with only weak parametric assumptions. Monte Carlo evidence demonstrates that the estimator can perform well in moderately-sized samples. As an application, we study the strategic decision of firms in spatially-separated markets to establish a presence on the Internet.




Topics in Mathematical Economics and Game Theory


Book Description

Since the publication of "Theory of Games and Economic Behavior" by von Neumann and Morgenstern, the concept of games has played an increasing role in economics. It also plays a role of growing importance in other sciences, including biology, political science, and psychology. Many scientists have made seminal advances and continue to be leaders in the field, including Harsanyi, Shapley, Shubik, and Selten. Professor Robert Aumann, in addition to his important contributions to game theory and economics, made a number of significant contributions to mathematics. This volume provides a collection of essays in mathematical economics and game theory, including cutting-edge research on noncooperative game theory and its foundations, bargaining theory, and general equilibrium theory. Also included is a reprint of Aumann's classic paper, "Acceptable Points in General Cooperative n-Person Games" and of the oft-cited, yet hard to find, paper by Maschler, "The Worth of a Cooperative Enterprise to Each Member". This book illustrates the wide range of applications of mathematics to economics, game theory, and social choice. The volume is dedicated to Professor Robert J. Aumann, Hebrew University, Jerusalem, Israel, for his contributions in mathematics and social sciences.




Mathematical Economics and Game Theory


Book Description




Discrete Mathematics and Game Theory


Book Description

This book describes highly applicable mathematics without using calculus or limits in general. The study agrees with the opinion that the traditional calculus/analysis is not necessarily the only proper grounding for academics who wish to apply mathematics. The choice of topics is based on a desire to present those facets of mathematics which will be useful to economists and social/behavioral scientists. The volume is divided into seven chapters. Chapter I presents a brief review of the solution of systems of linear equations by the use of matrices. Chapter III introduces the theory of probability. The rest of the book deals with new developments in mathematics such as linear and dynamic programming, the theory of networks and the theory of games. These developments are generally recognized as the most important field in the `new mathematics' and they also have specific applications in the management sciences.