Sharp test for equilibrium uniqueness in discrete games with a flexible information structure

I propose a test for an assumption commonly maintained when estimating static discrete games of incomplete information, i.e. the assumption of equilibrium uniqueness in the data generating process. The test is appealing for several reasons. It allows for discrete common knowledge payoff-relevant unobserved heterogeneity (henceforth unobserved heterogeneity, for short). In that sense, it is more general than tests which attribute all correlation between players’ decisions to multiple equilibria. Furthermore, the test does not require the estimation of payoffs to separate multiplicity of equilibria from unobservable heterogeneity. It is therefore useful in empirical applications leveraging multiple equilibria to identify the model’s primitives when commonly-used exclusion restrictions are not available. Finally, it makes no parametric assumption on the payoff functions nor the distribution of players’ private information. The main identifying assumption is the existence of an observable variable that plays the role of a proxy for the unobserved heterogeneity. The procedure boils down to testing the emptiness of the set of data generating processes that can rationalize the sample through a single equilibrium and a finite mixture over unobserved heterogeneity. Simulation evidence is provided to study the test’s properties

Games with unobservable heterogeneity and multiple equilibria: an application to mobile telecommunications

To shed light on the limited success of competition enhancing policies in mobile telecommunications, I estimate a game of transceivers’ locations between national incumbents and a new entrant in Canada. I recover player-specific unobserved heterogeneity from bids for spectrum licenses to address the unavailability of regressors required to identify incumbents’ responses to the new entrant’s decisions. I find that incumbents benefitting from important economies of density is a plausible explanation for policies’ drawbacks. I then evaluate the equilibrium effect of subsidizing the new entrant’s transceivers and find that this alternative proposition increases its investments while only slightly modifying incumbents’

Imposing equilibrium restrictions in the estimation of dynamic discrete games

Imposing equilibrium restrictions provides substantial gains in the estimation of dynamic discrete games. Estimation algorithms imposing these restrictions – MPEC, NFXP, NPL, and variations – have different merits and limitations. MPEC guarantees local convergence, but requires the computation of high-dimensional Jacobians. The NPL algorithm avoids the computation of these matrices, but – in games – may fail to converge to the consistent NPL estimator. We study the asymptotic properties of the NPL algorithm treating the iterative procedure as performed in finite samples. We find that there are always samples for which the algorithm fails to converge, and this introduces a selection bias. We also propose a spectral algorithm to compute the NPL estimator. This algorithm satisfies local convergence and avoids the computation of Jacobian matrices. We present simulation evidence illustrating our theoretical results and the good properties of the spectral algorithm

Un modèle de prévision de la demande de gaz naturel au Québec

Tableau d’honneur de la Faculté des études supérieures et postdoctorales, 2010-2011L'objectif premier de la présente recherche est de développer un modèle économétrique pouvant être utilisé pour prévoir la consommation de gaz naturel au Québec dans les secteurs résidentiel et affaires (lequel regroupe les clients commerciaux et institutionnels). Des prévisions adéquates sont nécessaires pour les distributeurs de gaz naturel désirant réviser leurs tarifs ou planifier leurs approvisionnements gaziers. Un modèle ayant déjà été appliqué à la consommation totale d'énergie au Québec et ayant été reconnu pour ses propriétés prévisionnistes satisfaisantes constitue le point de départ de l'analyse. Différentes versions de ce modèle sont estimées et comparées afin de déterminer si l'introduction de certaines variantes permet d'améliorer sa capacité à prévoir la consommation réelle d'énergie. Parmi les variantes étudiées se trouvent la simplification de la spécification utilisée, l'introduction d'un effet de retard sur les variables de prix et la décomposition de ces variables selon leurs mouvements à la hausse ou à la baisse. Au final, le modèle de prévision suggéré est une version simplifiée du modèle intial qui remplace le prix réel du gaz naturel à une période donnée par le plus élevé des prix réels antérieurs à la période considérée. De plus, trois éléments peuvent être retenus de cette analyse. Premièrement, tandis que le modèle initial réplique assez bien la consommation totale d'énergie, ses prévisions de la consommation de gaz naturel s'écartent davantage de la consommation réelle. Deuxièmement, bien que la simplification du modèle permette généralement d'obtenir des prévisions plus fidèles à la réalité, Tintroduction d'un effet de retard sur les prix et la décomposition de ces mêmes variables ont des effets partagés sur les propriétés prévisionnistes. Troisièmement, quelques différences quant à l'ajustement de la consommation d'énergie dans le temps et à la significativité de certaines variables explicatives ont été remarquées après avoir comparé les estimations du modèle initial aux estimations qui avaient déjà été obtenues par d'autres auteurs

Micro-confinement of bacteria into w/o emulsion droplets for rapid detection and enumeration

International audienceToday, rapid detection and identification of bacteria in microbiological diagnosis is a major issue. Reference methods usually rely on growth of microorganisms, with the drawback of lengthy time-to-result. The method provides global information on a clonal population that is known to be inhomogeneous relative to metabolic states and activities. Therefore, there may be a significant advantage of methods that allow characterisation of individual bacteria from a large population, both for test time reduction and the clinical value of the characterisation. We report here a method for rapid detection and real-time monitoring of the metabolic activities of single bacteria. Water-in-oil emulsions were used to encapsulate single Escherichia coli cells into picolitre (pL)-sized microreactor droplets. The glucuronidase activity in each droplet was monitored using the fluorogenic reporter molecule MUG (4-methylumbelliferyl- - d-glucuronide) coupled to time-lapse fluorescence imaging of the droplets. Such bacterial confinement provides several major advantages. (1) Enzymatic activities of a large number of single bacterium-containing droplet could be monitored simultaneously, allowing the full characterisation of metabolic heterogeneity in a clonal population. We monitored glucuronidase enzymatic activity and growth over ∼200 single bacteria over a 24-h period. (2) Micro-confinement of cells in small volumes allows rapid accumulation of the fluorescent metabolite, hence decreasing the detection time. Independent of the initial concentration of bacteria in the sample, detection of the presence of bacteria could be achieved in less than 2 h. (3) Considering the random distribution of bacteria in droplets, this method allowed rapid and reliable enumeration of bacteria in the initial sample. Overall, the results of this study showed that confinement of bacterial cells increased the effective concentration of fluorescent metabolites leading to rapid (2 h) detection of the fluorescent metabolites, thus significantly reducing time to numeration

Identification, Estimation and Inference in Empirical Games

This thesis collects three papers studying topics related to the econometrics of empirical games. In Chapter 1, I investigate the identification and the estimation of empirical games of incomplete information with common-knowledge unobservable heterogeneity and potentially multiple equilibria realized in the data. I introduce pre-determined outcome variables to recover such unobserved heterogeneity. The recovered unobservables provide an extra source of exogenous variation that helps to identify the primitives of the model. I apply this method to study mobile telecommunications in Canada. I estimate a game in which national incumbents and new entrants choose the number of transceivers they install in different markets. The results highlight sizeable economies of density in transceivers location decisions. Counterfactual experiments shed light on the governmentâ s attempt to increase competition in this industry. In Chapter 2, I propose a test of an assumption commonly maintained when estimating discrete games of incomplete information, i.e. the assumption of equilibrium uniqueness in the data generating process. The test I propose is robust to player-specific common-knowledge unobservables. The main identifying assumption is the existence of an observable variable interpreted as a proxy for these unobservables. It must (i) have sufficient variation; (ii) be correlated with the common-knowledge unobservables; and (iii) provide only redundant information regarding the playersâ decisions and the equilibrium selection, were these unobservables actually observed. In Chapter 3, I study bias reduction when estimating dynamic discrete games. An iterative approach (the K-step estimator) is known to reduce finite sample bias, provided that some equilibrium stability conditions are satisfied. Modified versions of the K-step estimator have been proposed to deal with this stability issue. Alternatively, there exist other bias reduction techniques which do not rely on equilibriumâ s stability, but have not received much attention in this class of models. Using a dynamic game of market entry and exit, I compare the finite sample properties of the K-step approach with alternative methods. The results show that, even when the K-step estimator does not converge to a single point after a large number of iterations, it still considerably reduces finite sample bias for small values of K.Ph.D

La francophonie de demain : essai de mesure de la population appartenant à la francophonie d’ici 2050

Quel pourrait bien être l’effectif de la population appartenant à la francophonie ? Quelle est sa répartition à travers la planète, et quelle sera-t-elle dans les décennies à venir : la francophonie sera-t-elle concentrée dans quelques régions ? Dans un contexte où mondialisation semble rimer avec anglicisation, il nous a paru intéressant de tenter un exercice prospectif pour cerner ce que sera la francophonie de demain, en examinant ses tendances démographiques sur les différents continents à l’aide des plus récentes projections des Nations Unies. Celles-ci, produites en 2002, ont la particularité de reposer sur une approche nouvelle qui permet d’entrevoir pour la planète un avenir démographique fort différent de celui qui avait été envisagé par le passé. En nous appuyant sur différentes définitions de l’espace francophone et en utilisant les nouvelles données de l’ONU, nous tentons dans cet article de mieux cerner les contours démographiques de la francophonie de demain, tout en relevant certains des enjeux politiques et sociaux de cet exercice prospectif.What will be the size of the population of la francophonie in the future? How is this population currently distributed worldwide and how will this change in coming decades? Will la francophonie be concentrated in a few regions? In a context where globalization often seems to mean “anglicization,” we felt that it would be interesting to try to predict the future of la francophonie, in looking at demographic trends in this regard on the various continents with the help of the latest United Nations projections. These projections, produced in 2002, are based on a new approach that raises the possibility of a demographic future for our planet that will be very different from the scenarios predicted in the past. By using various definitions of l’espace francophone along with the new UN data, we attempt in this article to more effectively delineate the demographic contours of la francophonie in the future, while also bringing out some of the political and social issues involved in this prospective exercise

Mid-infrared multispectral lensless imaging for wide-field and label-free microbial identification

SPIE Photonics Europe, 2020, Strasbourg, France. March 29, 2020 - April 2, 2020International audienceConsidering the optimization possibilities of the image descriptors currently used and the ongoing development of the uncooled bolometers technology, these very first results are promising and could be dramatically improved with further experiments. Thereby, mid-infrared multispectral lensless imaging has the potential to become a fast and precise Petri dish analysis technology

Conformational changes in p47 phox upon activation highlighted by mass spectrometry coupled to hydrogen/deuterium exchange and limited proteolysis

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