BONTEMPS Christian

This thesis consists of three chapters. The first chapter studies the effects of a subsidy in the case where firms can change the price as well as the characteristics of the product they offer. The second chapter (joint with Christian Bontemps and Cristina Gualdani) constructs and estimates a two-stage model of airline network competition. The third chapter (joint with Charles Pébereau) studies the adoption of real-time electricity pricing. In the first chapter, I study the economic effects of subsidies on the market for electric cars, which are subsidized around the world because they are seen as a key element in the de-carbonization of the transportation sector. In response to these subsidies, electric car producers have the ability to adjust not only the price of the cars but also their range. My analysis shows that the way in which these subsidies are implemented has an important impact on these price and range choices. In my study, I find that a subsidy directly indexed to range leads firms to sell electric cars that are more expensive and have more range. In contrast, a fixed subsidy leads firms to sell cheaper electric cars with less range. These effects have important implications for policy makers who have two objectives: While the quantity of electric cars sold is maximized with the fixed subsidy, minimizing CO2 emissions requires a trade-off between maximizing sales of electric cars and substituting high-polluting conventional cars. This trade-off is resolved with an intermediate subsidy. If a policymaker cannot achieve both goals with the same subsidy, he or she may well maximize electric car sales and the surplus of poorer consumers with the same subsidy. In the second chapter, written in collaboration with Christian Bontemps and Cristina Gualdani, we construct and estimate a two-stage model of the airline industry. In this model, airlines first choose their direct flight network before competing with its rivals. This two-stage game allows us to take into account the interdependence of the routes chosen by the firms. In addition, the model allows us to perform counterfactual analyses capable of providing robust predictions with respect to the price level, but also to the change in the firms' network. We show that hub-and-spoke networks lower marginal cost and increase fixed cost. We evaluate a merger between American Airlines and US Airways and compare it to the scenario of an American Airlines bankruptcy. We also evaluate countermeasures imposed on the merging firms and find that these measures were successful in limiting the loss of consumer surplus. In the third chapter, Charles Pébereau and I study the introduction of real-time electricity pricing in New Zealand and offer explanations for the low uptake of this pricing. Real-time pricing exposes consumers to the current price of electricity, which changes every half hour. We find that consumers who have adopted this technology most recently are very sensitive to current prices. Adoption rates fall sharply when current prices are high. During a crisis in current electricity prices, the share of consumers abandoning real-time pricing declines with their experience. These results suggest that, over time, consumers are less responsive to immediate price changes. Our results are useful in the debate about how to encourage consumers to adopt real-time pricing, such as opt-in or opt-out programs.

In this paper, we consider inference procedures for entry games with complete information. Due to the presence of multiple equilibria, we know that such a model may be set-identified without imposing further restrictions. We complete the model with the unknown selection mechanism and characterize geometrically the set of predicted choice probabilities, in our case, a convex polytope with many facets. Testing whether a parameter belongs to the identified set is equivalent to testing whether the true choice probability vector belongs to this convex set. Using tools from the convex analysis, we calculate the support function and the extreme points. The calculation yields a finite number of inequalities, when the explanatory variables are discrete, and we characterized them once for all. We also propose a procedure that selects the moment inequalities without having to evaluate all of them. This procedure is computationally feasible for any number of players and is based on the geometry of the set. Furthermore, we exploit the specific structure of the test statistic used to test whether a point belongs to a convex set to propose the calculation of critical values that are computed once and independent of the value of the parameter tested, which drastically improves the calculation time. Simulations in a separate section suggest that our procedure performs well compared with existing methods.

We analyze the identification and estimation of parameters B satisfying the incomplete linear moment restrictions E(zT (xB - y)) = E(zT u(x)) where z is a set of instruments and u(z) an unknown bounded scalar function. We first provide several empirically relevant examples of such a set-up. Second,we show that these conditions set identify B where the identified set is bounded and convex. We provide a sharp characterization of the identified set not only when the number of moment conditions is equal to the number of parameters of interest but also in the case in which the number of conditions is strictly larger than the number of parameters. We derive a necessary and sufficient condition of the validity of supernumerary restrictions, which generalizes the familiar Sargan condition. We also construct a test of the null hypothesis, B0 E B, whose level is asymptotically exact and which relies on the minimization of the support function of the set B - {Bo}. Inverting this test makes it possible to construct confidence regions with uniformly exact coverage probabilities. Some Monte Carlo and empirical illustrations are presented.

No summary available.

This paper considers moment-based tests applied to estimated quantities. We propose a general class of transforms of moments to handle the parameter uncertainty problem. The construction requires only a linear correction that can be implemented in sample and remains valid for some extended families of nonsmooth moments. We reemphasize the attractiveness of working with robust moments, which lead to testing procedures that do not depend on the estimator. Furthermore, no correction is needed when considering the implied test statistic in the out-of-sample case. We apply our methodology to various examples with an emphasis on the backtesting of value-at-risk forecasts.

In this paper we review the literature on static entry games and show how they can be used to estimate the market structure of the airline industry. The econometrics challenges are presented, in particular the problem of multiple equilibria and some solutions used in the literature are exposed. We also show how these models, either in the complete information setting or in the incomplete information one, can be estimated from i.i.d. data on market presence and market characteristics. We illustrate it by estimating a static entry game with heterogeneous firms by Simulated Maximum Likelihood on European data for the year 2015.

In this paper, we consider inference procedures for entry games with complete information. Due to the presence of multiple equilibria, we know that such a model may be set-identified without imposing further restrictions. We complete the model with the unknown selection mechanism and characterize geometrically the set of predicted choice probabilities, in our case, a convex polytope with many facets. Testing whether a parameter belongs to the identified set is equivalent to testing whether the true choice probability vector belongs to this convex set. Using tools from the convex analysis, we calculate the support function and the extreme points. The calculation yields a finite number of inequalities, when the explanatory variables are discrete, and we characterized them once for all. We also propose a procedure that selects the moment inequalities without having to evaluate all of them. This procedure is computationally feasible for any number of players and is based on the geometry of the set. Furthermore, we exploit the specific structure of the test statistic used to test whether a point belongs to a convex set to propose the calculation of critical values that are computed once and independent of the value of the parameter tested, which drastically improves the calculation time. Simulations in a separate section suggest that our procedure performs well compared with existing methods.

The French abstract was not provided by the author.

For the past 10 years, the topic of set identification has been much studied in the econometric literature. Classical inference methods have been generalized to the case in which moment inequalities and equalities define a set instead of a point. We review several instances of partial identification by focusing on examples in which the underlying economic restrictions are expressed as linear moments. This setting illustrates the fact that convex analysis helps not only for characterizing the identified set but also for inference. From this perspective, we review inference methods using convex analysis or inversion of tests and detail how geometric characterizations can be useful.

No summary available.

This thesis is a contribution to the study of equilibrium job search models. It is composed of three chapters. The first one is devoted to a review of the literature on the subject, the next two present the models we have developed which incorporate features already present in the first models of this kind. In particular, they allow an employee to make job-to-job transitions. Two forms of heterogeneity are considered: firm and worker heterogeneity. Chapter II considers only the case of heterogeneous firms while the last chapter considers both forms of heterogeneity in the same market. The equilibrium of the economy is analyzed in detail. It is shown that, when the distribution of firm productivity is continuous, there is a bijective relationship between the wage offered by a firm and labor productivity. Particular attention is paid to the properties of the equilibrium wage distributions induced by these models. Indeed, one of the drawbacks of the previously developed models is to generate a cross-sectional wage distribution that is incompatible with the observed distributions. We show that firm heterogeneity is necessary to obtain a good fit. Other qualitative results concern the influence of the shape of the tails of the productivity distribution on those of the wages offered. Finally, we take into account the introduction of a legal minimum wage and derive necessary and sufficient conditions for the wage distribution to peak at this minimum wage. We develop multi-stage semi-parametric structural estimation methods of these models, based on an inversion of the wage-productivity function. We use these methods to estimate these models on French data from the INSEE employment survey.