Identification and Estimation of Discrete Games of Complete Information

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.

Identification and Estimation of Discrete Games of Complete Information

We discuss the identification and estimation of discrete games with complete information. Following Bresnahan and Reiss, a discrete game is defined to be a generalization of a standard discrete choice model in which utility depends on the actions of other players. Using recent algorithms that compute the complete set of the Nash equilibria, 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 illustration, we study the strategic decisions of firms in spatially-separated markets in establishing a presence on the InternetEmpirical Industrial Organization, Simulation Based Estimation, Homotopies

Adaptive Lock-Free Data Structures in Haskell: A General Method for Concurrent Implementation Swapping

A key part of implementing high-level languages is providing built-in and default data structures. Yet selecting good defaults is hard. A mutable data structure's workload is not known in advance, and it may shift over its lifetime - e.g., between read-heavy and write-heavy, or from heavy contention by multiple threads to single-threaded or low-frequency use. One idea is to switch implementations adaptively, but it is nontrivial to switch the implementation of a concurrent data structure at runtime. Performing the transition requires a concurrent snapshot of data structure contents, which normally demands special engineering in the data structure's design. However, in this paper we identify and formalize an relevant property of lock-free algorithms. Namely, lock-freedom is sufficient to guarantee that freezing memory locations in an arbitrary order will result in a valid snapshot. Several functional languages have data structures that freeze and thaw, transitioning between mutable and immutable, such as Haskell vectors and Clojure transients, but these enable only single-threaded writers. We generalize this approach to augment an arbitrary lock-free data structure with the ability to gradually freeze and optionally transition to a new representation. This augmentation doesn't require changing the algorithm or code for the data structure, only replacing its datatype for mutable references with a freezable variant. In this paper, we present an algorithm for lifting plain to adaptive data and prove that the resulting hybrid data structure is itself lock-free, linearizable, and simulates the original. We also perform an empirical case study in the context of heating up and cooling down concurrent maps.Comment: To be published in ACM SIGPLAN Haskell Symposium 201

Helping Child Workers: How should multinational corporations accommodate child workers in Southeast Asian countries to which they outsource?

Outsourcing is one of the major supply chain strategies adopted by many multinational corporations in order to respond to market demand by lowering the cost. As the emphasis on social responsibility and sustainability has been increasing, there has been a lot of pressure on firms to control many problems caused by different living conditions or cultures. One of the most significant humanitarian issues is ongoing child labor practices. This paper describes how corporations, such as Nike, Reebok, Wal-Mart and the Pentland Group, have been addressing this issue. Many of them have been eliminating child labor among their suppliers; however, that policy is not a true meaning of social responsibility because child workers will search for alternative jobs that might provide worse working conditions. To address the child labor problems in developing countries in order to ultimately eradicate child labor, extensive research was conducted to find the most viable business model solution. The solution is directly focused on two countries in Southeast Asia, which are Bangladesh and Cambodia. Recommendations are made for multinational corporations to cooperate with non-governmental organizations as well as the national governments in depth, in order to acquire critical insights and experience to implement the solution. The core element of the business model is building a private school right next to the factory where child workers could acquire both education and household income. Instead of eliminating all child workers from the factories, by accommodating them, child labor will be eliminated gradually because their household income will rise. At the end, there will be no child workers to even employ for multinational corporations in Cambodia and Bangladesh

On the Forward-Backward Asymmetry of Leptonic Decays of ttˉt\bar{t} at the Fermilab Tevatron

We report on a study of the measurement techniques used to determine the leptonic forward-backward asymmetry of top anti-top quark pairs in Tevatron experiments with a proton anti-proton initial state. Recently it was shown that a fit of the differential asymmetry as a function of $q_{l}\eta_{l}$ (where $q_{l}$ is the charge of the lepton from the cascade decay of the top quarks and $\eta_{l}$ is the final pseudorapidity of the lepton in the detector frame) to a hyperbolic tangent function can be used to extrapolate to the full leptonic asymmetry. We find this empirical method to well reproduce the results from current experiments, and present arguments as to why this is the case. We also introduce two more models, based on Gaussian functions, that better model the $q_{l}\eta_{l}$ distribution. With our better understanding, we find that the asymmetry is mainly determined by the shift of the mean of the $q_{l}\eta_{l}$ distribution, the main contribution to the inclusive asymmetry comes from the region around $|q_{l}\eta_{l}| = 1$, and the extrapolation from the detector-covered region to the inclusive asymmetry is stable via a multiplicative scale factor, giving us confidence in the previously reported experimental results.Comment: 26 pages, 12 figure

Identification and Estimation of a Discrete Game of Complete Information

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. We demonstrate that the model is identified under weak functional form assumptions using exclusion restrictions and an identification at infinity approach. Monte Carlo evidence demonstrates that the estimator can perform well in moderately sized samples. As an application, we study entry decisions by construction contractors to bid on highway projects in California. We find that an equilibrium is more likely to be observed if it maximizes joint profits, has a higher Nash product, uses mixed strategies, and is not Pareto dominated by another equilibrium.National Science Foundation (U.S.) (Grant SES-0339328)National Science Foundation (U.S.) (Grant SES-0452143