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LUNCH SEMINAR 2014-2015

Juin 2015

Lundi 1er juin
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Olga GORELKINA (Max Planck Institute for Research on Collective Goods, Bonn)

Titre : "Selling Money on Ebay: A Case for Fairness Concerns"

with Alia Gizatulina (U. St. Gallen)

Résumé : To determine whether subjects display social preferences in a competitive market in the field, we conduct a trading experiment with a pool of German Ebay users. Acting as a seller, we offer Amazon gift cards with values from 5 to 500 euros. The randomly arriving buyers, subjects of our experiment, make take-it-or-leave-it price offers. From the distribution of offers we infer the splitting of the gains from trade that buyers propose to the seller. We find that 44% of the offers correspond to approximately equal sharing between the buyer and the seller. The amount of money at stake has no significant effect on the relative prices offered. Likewise, the offers are not affected by the public information about the number of competing buyers.

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Changements date et horaires:
Mardi 9 juin

11:00 - 12:00

Bibliothèque rez-de-chaussée - Département d'Economie

Olivier GOSSNER (Département d'Economie, Ecole Polytechnique)

Titre : "Competition and adverse selection: who wins the pot ?"

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Lundi 15 juin
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Robert SOMOGYI (Département d'Economie, Ecole Polytechnique)

Titre : "tba"

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Lundi 22 juin
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Gregory CORCOS (Département d'Economie, Ecole Polytechnique)

Titre : "tba"

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May 2015

Lundi 4 mai
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Alessandro IARIA (Crest)

Titre : "Estimating Demand Parameters with Choice Set Misspecification"  Joint work with Greg Crawford and Rachel Griffith.

Résumé : We describe methods to estimate demand parameters in the presence of choice set misspecification due to unobserved individual choice sets and/or endogenous matching of individuals to choice sets. We show that a consumer's probability of making a choice from her true (possibly endogenous) choice set can be written as the probability she makes the same choice from a universal choice set less two bias terms capturing the probabilities (1) that she would choose any of the elements in her true choice set and (2) that she was matched to that set. These bias terms are ignored in the vast majority of applications of differentiated product demand estimation, which estimate preferences based on a universal choice set. We provide monte carlo results demonstrating the magnitude of these biases and show how to estimate models that account for them with (i) a variation of the Fixed Effect Logit approach due to Chamberlain (1980) and (ii) using observed individual-specific purchase histories. We illustrate these ideas using household-level scanner data exploiting variation in choice sets based on store entry in the UK grocery market. Our results show that cccurately accounting for choice set misspecification is critical for accurately estimating own- and cross-price elasticities of demand.
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Lundi 11 mai
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Vincent PONS (Crest)

Titre : "Diversity and Team Performance in a Kenyan Organization"

Résumé : We present findings from a field experiment on team diversity. Individuals working as canvassers in an elections-related experiment were randomly assigned a teammate, a manager and a set of households to visit. This created random variation in the degree of horizontal diversity, vertical (or hierarchical) diversity and external (or client) diversity within each team. We find that ethnic diversity among teammates decreases team performance, while diversity along the vertical dimension improves effort and performance. The performance effect of ethnic homogeneity within teams is more than twice the size of the effect of homogeneity along gender or age lines. Results from a survey of the canvassers suggest that horizontally homogeneous teams organized tasks in a more efficient way, while vertically homogeneous teams exerted lower effort.

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Lundi 18 mai
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Raicho BOJILOV (Département d'Economie - Ecole Polytechnique)

Titre : "Informational Content of Interviews"

Résumé :  Interviews are crucial part of the hiring process but empirical work in the field has been limited. We use the personnel records of a large multinational call center company that contain detailed information about the demographics and work history of both interviewers and candidates. We study whether interviews are a useful sorting device for both the firm or the candidates. The data reveal that some interviewers are persistently better than average in their ability to screen candidates. We relate this persistence in interview performance to past interviewing experience, job title, work history, performance and the differences between the characteristics of the interviewer and the candidate.

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April 2015
Lundi 13 avril
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Allan DRAZEN (University of Maryland, Department of Economics, NBER, and CEPR)

Titre : "A Structural Model of Political Accountability"

Avec S. Borağan Aruoba et Razvab Vlaicu

This paper proposes a structural approach to the estimation of the effect of political accountability. We identify and quantify discipline and selection effects using U.S. gubernatorial elections for 1982-2012. We find that the possibility of re-election provides a significant incentive for incumbents to exert effort. We also find a selection effect, though it is weaker in terms of its effect on average governor performance. A structural approach also allows us to measure the welfare effects of different term limit lengths.
Contact : Alessandro Riboni

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March 2015

Lundi 2 mars
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Pierre PICARD et Alexis LOUAAS (Départment of Economics Ecole Polytechnique)

Titre :"Optimal insurance for catastrophic risk: theory and application to nuclear corporate liability"

Résumé : We analyze the optimal insurance coverage for high severity-low probability accidents, both from theoretical and applied standpoints. Such accidents qualify as catastrophic when their risk premium is a non-negligible proportion of the victims’ wealth, although the probability of occurrence is very small. We show that this may be the case when the individual’s absolute risk aversion is very large in the accident case. We characterize the optimal insurance contract firstly for an individual, and secondly for a firm that may be at the origin of an accident that affects the whole population. The optimal indemnity schedule converges to a limit when the probability of the accident tends to zero. In the case of corporate civil liability, this limit schedule is a straight deductible contract that corresponds to an indemnification of victims ranked in order of priority according to the severity of their losses. We also show that the size of the deductible depends on the individuals’ risk aversion and also on the cost of contingent risk capital that is required to sustain the indemnity payment, should an accident occur. The empirical part of the paper is an application of these general principles to the case of nuclear accidents. Large scale nuclear accidents are typical examples of high severity-low probability risks. We calibrate a model on French data in order to estimate the optimal liability ceiling of an electricity producer in the nuclear energy sector. We use data drawn from the cat-bond markets to estimate the cost of contingent capital for low probability events, and we show that the minimal corporate liability adopted in 2004 through the revision of the Paris Convention is probably lower than the level that would correspond to an optimal risk coverage of the population.

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Lundi 9 mars
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Christian BELZIL (Départment of Economics Ecole Polytechnique)

Titre : "Estimating the Value of Higher Education Financial Aid"

Avec Arnaud Maurel et Modibo Sidibe, Duke

Résumé : Using data drawn from a field experiment conducted in several Canadian high schools, we estimate a structural model of higher education financing. In the experiment, students may choose between immediate cash payments and a wide variety of loans and grants going from $400 to$4000. Because the experiment was also designed to elicit risk aversion and discount factors, we can estimate non-parametrically the distribution of preferences and decompose the willingness to pay for financial aid into a preference component and a parental background component. Our estimates indicate that the median agent would be willing to pay an additional rate of 3% to secure a loan comparable to those offered by Canadian institutions and give up $455 of current consumption for a$1,000 grant (subsidy). We find that the cross-sectional dispersion in the value of financial aid is mostly explained by risk aversion and by impatience and to a lesser extent by parental income.

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Lundi 16 mars
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Jean-Pierre PONSSARD (Départment of Economics Ecole Polytechnique)

Avec Guy Meunier et Francisco Ruiz-Aliseda

Résumé :In industries with large sunk costs, the investment strategy of competing firms depends on the regulatory context. We consider ex ante industrial policies in which the sunk cost may be either taxed or subsidized, and antitrust policies which could be either pro-competitive (leading to divestiture in case of high ex-post profitability) or lenient (allowing mergers in case of low ex-post profitability). Through a simple entry game we completely characterize the impact of these policies and examine their associated dynamic trade-offs between the timing of the investment, the ex-post benefits for the consumers, and the possible duplication of fixed costs. We find that merger policies are dominated by ex-ante industrial policies, whereas the latter are dominated by divestiture policies only under very special circumstances.

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Lundi 23 mars
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Guilhem LECOUTEUX (Départment of Economics Ecole Polytechnique)

Titre : "The Rationale of Team Reasoning"

Résumé : Team reasoning theory has been developed to overcome the predictive failures of standard game theory in cooperation and coordination games: it is assumed that in certain situations, the individuals can conceive themselves as the members of a team, and make their choices so as to satisfy the team’s objective. Unlike social preferences approaches in which we alter individual preferences, team reasoning implies a transfer of agency from the individual to the collective level, without requiring a modification of individual preferences. We develop a formal framework of team reasoning based on Bacharach's notion of unreliable team interaction, and define the collective preferences of the group as the result of a strategic choice. We show that the construction of collective preferences may lead to aggressive behaviours toward the players outside the team in submodular games. We can then show that, in a very large class of games, team reasoning is the only procedure of choice that rational individuals should adopt.

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Lundi 30 mars
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Anett JOHN (CREST-ENSAE)

Titre : "When Commitment Fails - Evidence from a Regular Saver Product in the Philippines"

Commitment products are widely regarded as a remedy for self-control problems. However, imperfect knowledge about one's preferences implies that individuals may fail to anticipate their behaviour under commitment, and consequently choose ill-suited commitment contracts. I conduct a randomised experiment in the Philippines, where low-income individuals were randomly offered a regular-instalment commitment savings product. Individuals chose the stakes of the contract (a default penalty) themselves. A majority appears to choose a harmful contract: While the intent-to-treat effect on individuals' bank savings is large, 55 percent of clients default on their savings contract. A possible explanation that is supported by the data is that the chosen stakes were too low (the commitment was too weak) to overcome clients' self-control problems. Both take-up and default are negatively predicted by measures of sophisticated hyperbolic discounting - suggesting that partial sophisticates adopt weak commitments and then default, while full sophisticates are more cautious about committing, but better able to choose incentive-compatible contracts.

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December 2014

Lundi 1er décembre
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Leonardo PEJSACHOWICZ  (New York University - Dept of Economics Ecole Polytechnique)

Titre : "Uncertainty and Stochastic Independence"

Résumé : We study preference based characterizations of stochastic independence in an Anscombe Aumann setting. We propose axioms that pin down different notions of independent product for two Bewley preferences. Thanks to the well known link between relevant priors of a relation over AA-acts and the Bewley representation of it's unambiguous part, this provides characterizations of stochastic independence for a wide class of preferences, basically all those satisfying Transitivity, Monotonicity, Risk-Independence and Archimedean Continuity.
Contact : Jean-Baptiste Michau

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Lundi 8 décembre
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Eduardo PEREZ  ( Dept of Economics Ecole Polytechnique)

Titre : "Evidence Based Mechanisms" avec Frédéric Koessler

Résumé: We study implementation with privately informed agents who can produce evidence. We define evidence based mechanisms as mechanisms such that the designer's contingent plan of action is consistent with available evidence, and characterize the social choice functions that are straightforwardly implementable by such mechanisms. Our results imply that any function that is implementable with transfers is also implementable with sufficient evidence. With private values, the efficient outcome is ex post implementable with budget balanced and individually rational transfers. In single-object auction and bilateral trade environments with interdependent values, the efficient allocation is implementable with budget balanced and individually rational transfers."

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November 2014

Lundi 3 novembre
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Thomas Le BARBANCHON (CREST)

Titre : "Optimal Partial Unemployment Insurance : Evidence from Bunching in the U.S."

Résumé : Partial unemployment insurance enables claimants to keep part of their unemployment benefits when they work in low-earnings jobs. In this paper, I use kinks in the U.S. partial unemployment insurance schedule to study the behavioral response of claimants to the program. When U.S. claimants earn over a state-specific threshold, termed the "disregard", their benefits are reduced at a 100% marginal tax rate above that amount. However, the reduction in current benefits leads to an increase in future benefits, by delaying the potential benefit exhaustion date. As a consequence, forward-looking claimants are taxed according to a dynamic marginal tax rate that is below 100%. To account for those mechanisms, I develop a dynamic model of claimants, who work in small jobs while searching for permanent jobs. I adapt the bunching formula of Saez (2010) to a context with benefit transfers. Using administrative data on weekly claims, I document substantial bunching of unemployment insurance claimants at the disregard level. I estimate that the earnings elasticity to the net-of-tax rate (at the intensive margin) lies between 0.1 and 0.2. Using simulations, I show that a more generous partial unemployment insurance schedule is more efficient, as the actual schedule induces claimants to restrain too much their earnings.
Contact : Jean-Baptiste Michau

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Lundi 24 novembre
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Edouard CHRETIEN /Victor LYONNET (Department of Economics, Ecole Polytechnique)

Résumé : This paper is motivated by empirical evidence on the evolution of the different components of the U.S. financial sector during the 2007-09 financial crisis, with a particular focus on commercial banks. While the size of "shadow" banks has shrunk abruptly when the crisis occurred, the "traditional" banking sector has remained surprisingly stable; its aggregate size even increased continuously. We argue this role was critical in that it is likely to have dampened the disruptive effects of fire sales by distressed intermediaries. This peculiar role of commercial banks motivates our investigation into what makes commercial banks different from the rest of the intermediaries within the financial sector. We build a model entailing an analysis of the transfer of assets among intermediaries in times of crises, shedding light on the role and business models of "shadow" versus "traditional" intermediaries in relationship to one another. We find that commercial banks’ "traditional" banking business - although it implies more regulation and is more costly to run - enables them to grow during distress times, thereby playing the role of a buffer in the financial system. We find that the differences in banks’business models lead them to hold different types of assets; traditional banks being able to hold those assets that entail the highest degree of information asymmetry."
Contact : Jean-Baptiste Michau

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September 2014
Lundi 22 septembre
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Guillaume HOLLARD (Department of Economics Ecole Polytechnique)

Titre : "Gender differences: evidence from field tournaments"

Résumé (draft): In most societies around the world, women are often disadvantaged in the labor market and represent only a small proportion of high social achievements. We here propose to address the question of the origin of this gender gap in a naturally occurring environment. Our study is based on a large panel of chess games played during international tournaments. Data are collected in more than 150 countries and, thanks to Elo rankings, we precisely observe the intrinsic ability of players. We document a strong and robust gender effect. The expected gain for females decreases by about 2% against a male opponent, compared to an otherwise similar female. This gender effect is found to be "universal" despite huge variations in females' situation around the globe: controlling for country fixed effects or the degree of gender inequality across countries has virtually no impact on the size of the effect.
Contact : Jean-Baptiste Michau
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Lundi 29 septembre
12:15 - 13:15
Bibliothèque rez-de-chaussée - Département d'Economie

Jeanne HAGENBACH (Départment of Economics Ecole Polytechnique)

Titre : "Communication with evidence in the lab" with Eduardo Perez-Richet

contatc : Jean-Baptiste Michau

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