Research

"On fait la science avec des faits, comme on fait une maison avec des pierres ; mais une accumulation de faits n’est pas plus une science qu’un tas de pierres n’est une maison." Henri Poincaré, 1908, 'La science et l'hypothèse', Flammarion (ed. 1917), p.168.

Works in Progress

[Abstract] Laws not only affect behavior due to changes in material payoffs, but they may also change the perception individuals have of societal norms, either by shifting them directly or by providing information on these norms. Using detailed daily survey data and exploiting the introduction of lockdown measures in the UK in the context of the COVID-19 health crisis, we provide causal evidence that the law drastically changed the perception of the norms regarding social distancing behaviors. We show this effect of laws on perceived norms is mostly driven by an informational channel.

Additional content. Executive summary / Résumé non technique. || Coverage by Vox.eu

Galbiati R., Henry E., Jacquemet N. Learning to Cooperate in the Shadow of the Law. Revised in June 2020 [slides]

[Abstract] How does the exposure to past institutions affect current cooperation? While a growing literature focuses on behavioral channels, we show how cooperation-enforcing institutions affect rational learning about the group's value. Strong institutions, by inducing members to cooperate , may hinder learning about intrinsic values in the group. We show, using a lab experiment with independent interactions and random rematching, that participants behave in accordance with a learning model, and in particular react differently to actions of past partners whether they were played in an environment with coercive enforcement or not.
[Release notes] Revised version of Sc Po Economics DP n°2019-06, supersedes "Learning, Spillovers and Persistence: Institutions and the Dynamics of Cooperation", CEPR DP n°12128.

Hergueux J., Jacquemet N., Luchini S., Shogren J.F., Leveraging the Honor Code for Nature: Public Good Contributions under Oath, Revised in October 2020.

[Abstract] Public good games are at the core of many environmental challenges. But these public good games are notorious for producing neither pure free riding nor pure cooperative behavior. Rather most people prefer to cooperate–but only if the other players cooperate too. These “conditional cooperators” face a trade-off between their cooperative preferences and their self- interested material payoff given economic incentives trigger non-cooperative behavior. Herein we explore whether the preference revelation properties of the classic voluntary contribution game can be improved by offering players the possibility to sign a truth-telling oath. We provide testbed evidence using on a classic voluntary contribution induced value public goods game. Our results suggest the oath can help increase cooperation (by 33%). This change is associated with (i) strengthened reciprocal preferences–the oath increased the share of (per- fect) reciprocators; and (ii) a shift in first-order beliefs towards higher contributions expected from others. By examining the gaps between actual behavior and basic predictions based on first-order beliefs, reciprocal preferences and normative opinions, we conclude that the commitment to truth-telling induced by the oath leads to contributions that are more aligned with the cooperative preferences of subjects, and less sensitive to the strategic implications of the decision.
[Release notes] revised version of PSE WP n°2016-22.

Jacquemet N., Luchini S., Shogren J.F., Watson V. Discrete Choice under Oaths. CES WP n° 2019.07, April 2019 [slides]

[Abstract] Using discrete choices to elicit preferences is a major tool to help guide public policy. Although Discrete Choice Experiment (DCE) remains by far the most popular mechanism used to elicit preferences, its reliability still is questionable. Using an induced value experimental design, we show that standard benchmarks achieve no more than 56% (hypothetical answers with no monetary incentives) to 60% (real monetary incentives) of payoff maximizing choices. Herein we demonstrate that having respondents sign a the truth-telling oath reduces non-payoff maximizing choices by nearly 50% relative to these benchmarks. The explicit and voluntary commitment to honesty improved decisions. Further, we show that it is the explicit commitment to honesty induced by the truth-telling oath improves choices, not just any oath mechanism, i.e., an oath to task or to duty did not improve choices.
[Release notes] An earlier version previously circulated under the title: "Using Commitment to Improve Choice Experiment Survey Responses".
[Abstract] Based on panel data concerning physicians, who could adopt either the standard fee-for-service contract or a mixed remuneration contract under which they would receive a per diem and a reduced fee-for-service, we estimate a structural econometric model that incorporates service intensity (services per hour) and contract choice into a labour supply framework. We simulate labour supply elasticity's and predict the effects of contract form and other counterfactual reforms on behaviour. Among other things, doctors reduce their service intensity under MR contracts; their hours worked are less sensitive to incentives.
[Release notes] Revised version of CRREP WP n°2019-05, IZA DP n°5188, CIRANO WP n°2010s-40 and CIRPEE WP n°10-34.

Additional content. Executive summary / Résumé non technique || Coverage by Au fil des évenements, Contact-ULaval.

Jacquemet N. Corruption as Betrayal: Experimental Evidence. November 2012. Definitely sleeping....

[Abstract] Reciprocity between the briber and the bribee (an agent receiving a bribe to take a corrupt decision) has long been recognized as a corruption enforcement device. This paper focuses on the incentives to betray the corruption contract when the work contractof the bribee relies on gift exchange. In that situation, the bribee (agent) faces conflicting interests to reciprocate in favor of either the employer (the principal) or the briber. An experiment is designed based on a three-players corruption game featuring this trade-off. The baseline considers only the agent-briber relationships, while the main treatment of interest explicitly involves a principal deciding on how much the agent earns – whatever his subsequent behavior. Further treatments implement different levels of the wage earned by the agent. Experimental evidence supports the two main mechanisms of interest: corruption is lower when the wage earned has been chosen in a fair way by a principal. This implies a decreasing relationships between the level of corruption and the level of wages.
[Release note] An earlier version previously circulated as How Wages Affect Corruption Behavior: an Experimental Investigation of Delegation Consequences, GATE WP n°2005-06.

Published papers

(a list of selected publications is available here)

Jacquemet N., James A., Luchini S., Murphy J., Shogren J.F. Do Truth-Telling Oaths Improve Honesty in Crowd-Working?, PloS ONE, forthcoming. [free download]

[Abstract] This study explores whether an oath to honesty can reduce both shirking and lying among crowd-sourced internet workers. Using a classic coin-flip experiment, we first confirm that a substantial majority of Mechanical Turk workers both shirk and lie when reporting the number of heads flipped. We then demonstrate that lying can be reduced by first asking each worker to swear voluntarily on his or her honor to tell the truth in subsequent economic decisions. Even in this online, purely anonymous environment, the oath significantly reduced the percent of subjects telling "big" lies (by roughly 27%), but did not affect shirking. We also explore whether a truth-telling oath can be used as a screening device if implemented after decisions have been made. Conditional on flipping response, MTurk shirkers and liars were significantly less likely to agree to an ex-post honesty oath. Our results suggest oaths may help elicit more truthful behavior, even in online crowd-sourced environments.
[Release notes] Supersedes "Lying and shirking under oath", Economic Science Institute WP n°278

Replication material. Experimental instructions.

Jacquemet N., Luchini S., Malézieux A., Shogren J.F. (2020). Who’ll stop lying under oath? Empirical evidence from Tax Evasion Games, European Economic Review, Vol. 20, pp. 103369 (lead article). [free download] [slides]

[Abstract] Using two earned income/tax declaration experimental designs we show that only partial liars are affected by a truth-telling oath, a non-price commitment device. Under oath, we see no change in the number of chronic liars and fewer partial liars. Rather than smoothly increasing their compliance, we also observe that partial liars who respond to the oath, respond by becoming fully honest under oath. Based on both response times data and the consistency of subjects when several compliance decisions are made in a row, we show that partial lying arises as the result of weak preferences towards profitable honesty. The oath only transforms people with weak preferences for lying into being committed to the truth.
[Release notes] Revised version of TARC Discussion Paper n°027-19.

Replication material. Experimental Instructions [French] || Data and programs.

Additional content. Résumé non technique.

Jacquemet N., Luchini S., Malézieux A., Shogren J.F. (2019). A psychometric investigation of the personality traits underlying individual tax morale. The B.E. Journal of Economic Analysis and Policy, Vol. 19(3) [free download]

[Abstract] Why do people pay taxes? Rational choice theory has fallen short in answering this question. Another explanation, called "tax morale", has been promoted. Tax morale captures the behavioral idea that non-monetary preferences (like norm-submission, moral emotions and moral judgments) might be better determinants of tax compliance than monetary trade-offs. Herein we report on two lab experiments designed to assess whether norm-submission, moral emotions (e.g., affective empathy, cognitive empathy, propensity to feel guilt and shame) or moral judgments (e.g., ethics principles, integrity, and moralization of everyday life) can help explain compliance behavior. Although we find statistically significant correlations of tax compliance behavior with empathy and shame, the economic significance of these correlations are low more than 80% of the variability in compliance remains unexplained. These results suggest that tax authorities should focus on the institutional context, rather than individual preference characteristics, to handle tax evasion.
[Release notes] Also available as TARC Discussion Paper n°024-19.

Replication material. Screen shots of the experiment decision screens.

Edo A., Jacquemet. N., Yannelis C. (2019). Language Skills and Homophilous Hiring Discrimination: Evidence from Gender- and Racially-Differentiated Applications. Review of Economics of the Household, Vol. 17(1), pp. 349–376 [free download] [slides]

[Abstract] This paper investigates the importance of ethnic homophily in the hiring discrimination process. Our evidence comes from a correspondence test performed in France in which we use three different kinds of ethnic identification: French sounding names, North African sounding names, and “foreign” sounding names with no clear ethnic association. Within the groups of men and women, we show that all non-French applicants are equally discriminated against when compared to French applicants. Moreover, we find direct evidence of ethnic homophily: recruiters with European names are more likely to call back French named applicants. These results show the importance of favoritism for in-group members. To test for the effect of information about applicant’s skills, we also add a signal related to language ability in all resumes sent to half the job offers. The design allows to uniquely identify the effect of the language signal by gender. Although the signal inclusion significantly reduces the discrimination against non-French females, it is much weaker for male minorities.
[Release notes] Revised version of CES WP n°13-58.

Replication material. Translated resumes || Original resumes in french.

Additional content. Video: #OnVautMieuxQueCa, Talk at CEPREMAP || Executive summary / Résumé non technique || Coverage by The Economist, Atlantico.fr, Alternatives Economiques, Les Echos.fr, Le Monde (1), A.M.A.R.E., Emploi-Parlonsnet, Le Parisien.fr, Stylist, Le Monde (2), BBC.

Jacquemet N., Luchini S., Rosaz J., Shogren J.F. (2019). Truth-Telling under Oath. Management Science, Vol. 65 (1), pp. 426-438 [free download] [slides]

[Abstract] Oath taking for senior executives has been promoted as a means to enhance honesty within and toward organizations. Herein we explore whether people who voluntarily sign a solemn truth-telling oath are more committed to sincere behavior when offered the chance to lie. We design an experiment to test how the oath affects truth telling in two contexts: a neutral context replicating the typical experiment in the literature, and a “loaded” context in which we remind subjects that “a lie is a lie.” We consider four payoff configurations, with differential monetary incentives to lie, implemented as within-subjects treatment variables. The results are reinforced by robustness investigations in which each subject made only one lying decision. Our results show that the oath reduces lying, especially in the loaded environment—falsehoods are reduced by 50%. The oath, however, has a weaker effect on lying in the neutral environment. The oath did affect decision times in all instances: the average person takes significantly more time deciding whether to lie under oath.
[Release notes] Revised and extended version of CES WP n°2015-68.

Replication material. Experimental instructions.

Additional content. TEDx talk.

Galbiati R., Henry E., Jacquemet N. (2018). Dynamic effects of enforcement on cooperation. Proceedings of the National Academy of Sciences, Vol. 115 (49), pp. 12425-12428 [free download].

[Abstract] In situations where social payoffs are not aligned with private incentives, enforcement with fines can be a way to sustain cooperation. In this paper we show, by the means of a laboratory experiment, that past fines can have an effect on current behavior even when no longer in force. We document two mechanisms: (i) Past fines affect directly individuals’ future propensity to cooperate, and (ii) when fines for noncooperation are in place in the past, individuals experience higher levels of cooperation from partners and, consistent with indirect reciprocity motives, are in turn nicer toward others once these fines have been removed. This second mechanism is empirically prevalent and, in contrast with the first one, induces a snowball effect of past enforcement. Our results can inform the design of costly enforcement policies.

Additional content. Executive summary / Résumé non technique.

Jacquemet N., Luchini S., Shogren J.F., Zylbersztejn A. (2018). Coordination with Communication under Oath. Experimental Economics, Vol. 21 (3), pp. 627-649 [free download] [slides]

[Abstract] We focus on the design of an institutional device aimed to foster coordination through communication. We explore whether the social psychology theory of commitment, implemented via a truth-telling oath, can reduce coordination failure. Using a classic coordination game, we ask all players to sign voluntarily a truth-telling oath before playing the game with cheap talk communication. Three results emerge with commitment under oath: (1) coordination increased by nearly 50%; (2) senders’ messages were significantly more truthful and actions more efficient, and (3) receivers’ trust of messages increased.
[Release notes] Revised and augmented version of GREQAM WP n°2011-49.

Replication material. Experimental instructions. Supplementary Material. Neutral Announcements vs Promises.

Additional content. TEDx talk || Executive summary / Résumé non technique || Coverage by Le Monde.

Goussé, M., Jacquemet N., Robin J-M. (2017). Marriage, Labor Supply, and Home Production. Econometrica, Vol. 85 (6), pp. 1873-1919 [free download] [slides]

[Abstract] We develop a search model of marriage where men and women draw utility from private consumption and leisure, and from a non‐market good that is produced in the home using time resources. We condition individual decisions on wages, education, and an index of family attitudes. A match‐specific, stochastic bliss shock induces variation in matching given wages, education, and family values, and triggers renegotiation and divorce. Using BHPS (1991–2008) data, we take as given changes in wages, education, and family values by gender, and study their impact on marriage decisions and intrahousehold resource allocation. The model allows to evaluate how much of the observed gender differences in labor supply results from wages, education, and family attitudes. We find that family attitudes are a strong determinant of comparative advantages in home production of men and women, whereas education complementarities induce assortative mating through preferences.
[Release notes] Revised version of CIRPEE WP n°2015-68.

Goussé, M., Jacquemet N., Robin J-M. (2017). Household Labour Supply and the Marriage Market in the UK, 1991-2008. Labour Economics, Vol. 41, pp. 131-149 [free download] [slides]

[Abstract] We document changes in labour supply, wage and education by gender and marital status using the British Household Panel Survey, 1991-2008, and seek to disentangle the main channels behind these changes. To this end, we use a version of Goussé et al. (2016)'s search-matching model of the marriage market with labour supply, which does not use information on home production time inputs. We derive conditions under which the model is identified. We estimate different parameters for each year. This allows us to quantify how much of the changes in labour supply, wage and education by gender and marital status depends on changes in the preferences for leisure of men and women and how much depends on changes in homophily.
[Release notes] Revised and augmented version of CeMMAP WP n°07-13, untitled Assortative Matching and Search with Labor Supply and Home Production, superseding Marriage with Labour supply, CES WP n°2011-50.

Additional content. Executive summary [1] [2] / Résumé non technique.

Jacquemet N., James A., Luchini S., Shogren J.F. (2017). Referenda under Oath. Environmental & Resource Economics, Vol. 65(3), pp. 479-504 [free download] [slides]

[Abstract] Herein we explore whether a solemn oath can eliminate hypothetical bias in a voting referenda, a popular elicitation mechanism promoted in non-market valuation exercises for its incentive compatibility properties. First, we reject the null hypothesis that a hypothetical bias does not exist. Second, we observe that people who sign an oath are significantly less likely to vote for the public good in a hypothetical referenda. We complement this evidence with a self-reported measure of honesty which confirms that the oath increases truthfulness in answers. This result opens interesting avenues for improving the elicitation of preferences in the lab and beyond.
[Release notes] Revised and augmented version of GREQAM WP n°2010-15.

Replication material Experimental instructions.

Additional content. TEDx talk || Executive summary / Résumé non technique.

Le Lec F., Alexopoulos T., Boulu-Reshef B., Fayant M-P, Zenasni F., Lubart T., Jacquemet N. (2017). Courtship behavior: “The Out-of-my-league effect”. Behavioral and Brain Sciences, Vol. 40, e32 [free download].

[Abstract] When taking into account the chances of success, strategic mating motivations do imply a bias not toward the most attractive individuals, but toward average or mildly attractive individuals, undermining the explanation of Maestripieri et al. at a fundamental level. This leaves open the possibility of alternative explanations and calls for a full-fledged explicit model of courtship behavior.

Hanaki N., Jacquemet N., Luchini S., Zylbersztejn A. (2016). Fluid intelligence and cognitive reflection in a strategic environment: evidence from dominance-solvable games. Frontiers in Psychology, Vol. 8, Article 1188 [free download] [slides].

[Abstract] Dominance solvability is one of the most straightforward solution concepts in game theory. It is based on two principles: dominance (according to which players always use their dominant strategy) and iterated dominance (according to which players always act as if others apply the principle of dominance). However, existing experimental evidence questions the empirical accuracy of dominance solvability. In this study, we study the relationships between the key facets of dominance solvability and two cognitive skills, cognitive reflection, and fluid intelligence. We provide evidence that the behaviors in accordance with dominance and one-step iterated dominance are both predicted by one's fluid intelligence rather than cognitive reflection. Individual cognitive skills, however, only explain a small fraction of the observed failure of dominance solvability.

Additional content. Executive summary / Résumé non technique.

Hanaki N., Jacquemet N., Luchini S., Zylbersztejn A. (2015). Cognitive ability and the effect of strategic uncertainty. Theory and Decision, Vol. 81(1), pp. 101-122 [free download]

[Abstract] How is one’s cognitive ability related to the way one responds to strategic uncertainty? We address this question by conducting a set of experiments in simple 2×2 dominance solvable coordination games. Our experiments involve two main treatments: one in which two human subjects interact, and another in which one human subject interacts with a computer program whose behavior is known. By making the behavior of the computer perfectly predictable, the latter treatment eliminates strategic uncertainty. We find that subjects with higher cognitive ability are more sensitive to strategic uncertainty than those with lower cognitive ability.
[Release notes] Also available as GATE WP n°2015-29, revised version of AMSE n°2014-58; an earlier version previously circulated as Bounded rationality and strategic uncertainty in a simple dominance solvable game, University of Western Australia WP n°13-14.

Additional content. Executive summary [1] [2] / Résumé non technique.

Hergueux J., Jacquemet N. (2015). Social Preferences in the online laboratory: A randomized Experiment. Experimental Economics, Vol. 18(2), pp. 252-283 [free download] [Slides]

[Abstract] Internet is a very attractive technology for the implementation of experiments, both in order to obtain larger and more diverse samples and as a field of economic research in its own right. This paper reports on an experiment performed both online and in the laboratory, designed to strengthen the internal validity of decisions elicited over the Internet. We use the same subject pool, the same monetary stakes and the same decision interface, and control the assignment of subjects between the Internet and a traditional university laboratory. We apply the comparison to the elicitation of social preferences in a Public Good game, a dictator game, an ultimatum bargaining game and a trust game, coupled with an elicitation of risk aversion. This comparison concludes in favor of the reliability of behaviors elicited through the Internet. We moreover find a strong overall parallelism in the preferences elicited in the two settings. The paper also reports some quantitative differences in the point estimates, which always go in the direction of more other-regarding decisions from online subjects. This observation challenges either the predictions of social distance theory or the generally assumed increased social distance in internet interactions.
[Release notes] Revised and augmented version of CES WP n°2012-70.

Supplementary Material. Results from companion treatments.

Additional content. Talk at Berkman Center || Executive summary / Résumé non technique.

Jacquemet N., Zylbersztejn A. (2014). What drives failure to maximize payoffs in the lab? A test of the inequality aversion hypothesis. Review of Economic Design, Vol. 18(4), pp. 243-264 [free download]

[Abstract] Experiments based on the Beard and Beil (Manag Sci 40(2):252–262, 1994) two-player coordination game robustly show that coordination failures arise as a result of two puzzling behaviors: (i) subjects are not willing to rely on others’ self-interested maximization, and (ii) self-interested maximization is not ubiquitous. Such behavior is often considered to challenge the relevance of subgame perfectness as an equilibrium selection criterion, since weakly dominated strategies are actually used. We report on new experiments investigating whether inequality in payoffs between players, maintained in most lab implementations of this game, drives such behavior. Our data clearly show that the failure to maximize personal payoffs, as well as the fear that others might act this way, do not stem from inequality aversion. This result is robust to varying the saliency of decisions, repetition-based learning and cultural differences between France and Poland.
[Release notes] Revised and augmented version of CES WP n°2011-36.

Replication material. Experimental instructions.

Jacquemet N., Zylbersztejn A. (2013). Learning, words and actions: experimental evidence on coordination-improving information. The B.E. Journal of Theoretical Economics, Vol. 13(1), Contributions pp. 215-247 [free download] [slides]

[Abstract] We experimentally study an asymmetric coordination game with two Nash equilibria: one is Pareto-efficient, the other is Pareto-inefficient and involves a weakly dominated strategy. We assess whether information about the interaction partner helps eliminate the imperfect equilibrium. Our treatments involve three information-enhancing mechanisms: repetition and two kinds of individual signals: messages from partner or observation of his past choices. Repetition-based learning increases the frequencies of the most efficient outcome and the most costly strategic mismatch. Moreover, it is superseded by individual signals. Like previous empirical studies, we find that signals provide a screening of partners’ intentions that reduces the frequency of coordination failures. Unlike these studies, we find that the transmission of information between partners, either via messages or observation, does not suffice to significantly increase the overall efficiency of outcomes. This happens mostly because information does not restrain the choice of the dominated action by senders.
[Release notes] Revised version of CES WP n°2010-64.

Replication material. Experimental instructions.

Jacquemet N., Koessler F. (2013). Using or Hiding Private Information? An Experimental Study of Zero-Sum Repeated Games with Incomplete Information. Games and Economic Behavior, Vol. 78(1), pp. 103-120 [free download] [slides]

[Abstract] This paper studies the value of private information in strictly competitive interactions in which there is a trade-off between (i) the short-run gain of using information, and (ii) the long-run gain of concealing it. We implement simple examples from the class of zero-sum repeated games with incomplete information. While the empirical value of information does not always coincide with the theoretical prediction, the qualitative properties of the value of information are satisfied in the laboratory: (i) it is never negative, (ii) it decreases with the number of repetitions, (iii) it is bounded below by the value of the infinitely repeated game, and (iv) it is bounded above by the value of the one-shot game. In line with the theory, the empirical use of private information is almost complete when it should be, and decreases in longer interactions.
[Release notes] Revised version of CES WP n°2011-02.

Replication material. Experimental instructions. Supplementary material. Additional statistical analysis.

Additional content. Executive summary / Résumé non technique.

Jacquemet N., Joule R-V., Luchini S., Shogren J.F. (2013). Preference Elicitation under Oath. Journal of Environmental Economics and Management, Vol. 65(1), pp. 110–132 [free download] [slides]

[Abstract] Eliciting sincere preferences for non-market goods remain a challenge due to the discrepency between hypothetical and real behavior and false zeros. The gap arises because people either overstate hypothetical values or understate real commitments or a combination of both. Herein we examine whether the traditional real-world institution of the solemn oath can improve preference elicitation. Applying the social psychology theory on the oath as a truth-telling-commitment device, we ask our bidders to swear on their honour to give honest answers prior to participating in an incentive-compatible second-price auction. The oath is an ancillary mechanism to commit bidders to bid sincerely in a second-price auction. Results from our induced valuation testbed treatments suggest that the oath-only auctions outperform all our other auctions (real and hypothetical). In our homegrown valuation treatments eliciting preferences for dolphin protection, the oath-only design induced people to treat as binding both their experimental budget constraint (i.e., lower values on the high end of the value distribution) and participation constraint (i.e., positive values in place of the zero bids used to opt-out of auction). Based on companion treatments, we show the oath works through an increase in the willingness to tell the truth, due to a strengthening of the intrinsic motivation to do so.
[Release notes] Revised and augmented version of CES WP n°2009-43.

Additional content. TEDx talk || Résumé non technique || Coverage by Economic Logic.

Jacquemet N., Yannelis C. (2012). Indiscriminate Discrimination: A Correspondence Test for Ethnic Homophily in the Chicago Labor Market. Labour Economics, Vol. 19(6), pp. 824-832 [free download] [slides]

[Abstract] Numerous field experiments have demonstrated the existence of discrimination in labor markets against specific minority groups. This paper uses a correspondence test to determine whether this discrimination is due to prejudice against specific groups, or a general preference for the majority group. Three groups of identical fabricated resumes are sent to help-wanted advertisements in Chicago newspapers: one with Anglo-Saxon names, one with African-American names, and one with fictitious foreign names whose ethnic origin is unidentifiable to most Americans. Resumes with Anglo-Saxon names generate nearly one third more call-backs than identical resumes with non Anglo-Saxon ones, either African-American or Foreign. We take this as evidence that discriminatory behavior is part of a larger pattern of unequal treatment of any member of non-majority groups, ethnic homophily.
[Release notes] Revised version of CES WP n°2011-13.

Replication material. Name survey || Resumes || Data file.

Additional content. Executive summary.

Jacquemet N., Joule R-V., Luchini S., Shogren J.F. (2011). Do people always pay less than they say? Testbed laboratory experiments with IV and HG values. Journal of Public Economic Theory, Vol. 13(5), pp. 857-882 [free download]

[Abstract] Hypothetical bias is a long‐standing issue in stated preference and contingent valuation studies—people tend to overstate their preferences when they do not experience the real monetary consequences of their decision. This view, however, has been challenged by recent evidence based on the elicitation of induced values (IV) in the lab and homegrown (HG) demand function from different countries. This paper uses an experimental design to assess the extent and relevance of hypothetical bias in demand elicitation exercises for both induced (IV) and homegrown (HG) values. For testbed purpose, we use a classic second‐price auction to elicit preferences. Comparing the demand curve we elicit in both, hypothetical bias unambiguously (i) vanishes in an IV, private good context and (ii) persists in HG values elicitation context. This suggests hypothetical bias in preference elicitation appears to be driven by “preference formation” rather than “preference elicitation.” In addition, companion treatments highlight two sources of the discrepancy observed in the HG setting: the hypothetical context leads bidders to underestimate the constraints imposed by their budget limitations, whereas the real context creates pressure leading them to bid “zero” to opt out from the elicitation mechanism. As a result, there is a need for a demand elicitation procedure that helps subjects take the valuation exercise sincerely, but without putting extra pressure on them.
[Release notes] Earlier version: GREQAM WP n°2009-44; part of this paper previously circulated as Do French students really bid sincerely?, GREQAM WP n°2008-12.

Replication material. Experimental instructions || Opt-out decision screen.

Additional content. Résumé non technique.

Jacquemet N., James A., Luchini S., Shogren J.F. (2011). Social psychology and environmental economics: a new look at ex ante corrections of biased preference evaluation. Environmental & Resource Economics, Vol. 48(3), pp. 411-433 [free download]

[Abstract] The field of social psychology explores how a person behaves within the context of other people. The social context can play a substantive role in non-market allocation decisions given peoples choices and values extend beyond the classic market-based exchange institution. Herein we explore how social psychology has affected one aspect of environmental economics: preference elicitation through survey work. We discuss social representation, social isolation, framing through cheap talk, and commitment theory through an oath.
[Release notes] Earlier version: CES WP n°2010-16.

Replication material. Instructions for the HG experiment || Instructions for the IV Experiment || Quizz used in Part 1 || HG Decision Screen || Cheap talk script for the IV experiment || Cheap talk script for the HG experiment.

Jacquemet N., Joule R-V., Luchini S., Shogren J.F. (2009). Earned Wealth, Engaged Bidders? Evidence from a second price auction. Economics Letters, Vol. 105(1), pp. 36-38 [free download]

[Abstract] This paper considers whether earned wealth affects bidding behavior in an induced-value second-price auction. We find people bid more sincerely in the auction with earned wealth given monetary incentives; earned wealth did not induce sincere bidding in hypothetical auctions.
[Release notes] Earlier version: GREQAM WP n°2008-13.

Replication material. Experimental instructions.

Dumont E., Fortin B., Jacquemet N., Shearer B. (2008). Physicians' Multitasking and Incentives: Empirical Evidence from a Natural Experiment. Journal of Health Economics, Vol. 27(6), pp. 1436-1450 [free download]

[Abstract] We analyse how physicians respond to contractual changes and incentives within a multitasking environment. In 1999 the Quebec government (Canada) introduced an optional mixed compensation (MC) system, combining a fixed per diem with a partial (relative to the traditional fee-for-service (FFS) system) fee for services provided. We combine panel survey and administrative data on Quebec physicians to evaluate the impact of this change in incentives on their practice choices. We highlight the differentiated impact of incentives on various dimensions of physician behaviour by considering a wide range of labour supply variables: time spent on seeing patients, time devoted to teaching, administrative tasks or research, as well as the volume of clinical services and average time per clinical service. Our results show that, on average, the reform induced physicians who changed from FFS to MC to reduce their volume of (billable) services by 6.15% and to reduce their hours of work spent on seeing patients by 2.57%. Their average time spent per service increased by 3.81%, suggesting a potential quality–quantity substitution. Also the reform induced these physicians to increase their time spent on teaching and administrative duties (tasks not remunerated under the fee-for-service system) by 7.9%.
[Release notes] Earlier versions: IZA DP n°3229 and CIRPEE WP n°07-45.

Additional content. Résumé non technique.

Fortin B., Jacquemet N., Shearer B. (2008). Policy Analysis in the health-services market: accounting for quality and quantity. Annales d’Economie et de Statistiques, Vol.91-92, pp. 287-313 [free download] [Slides in french]

[Abstract] We provide a theoretical and empirical framework for evaluating the effects of policy reforms on physician labor supply. We argue that any policy evaluation must account for both the quality and the quantity of services provided. The introduction of quality into the analysis has implications for both the theoretical and empirical analysis of labor supply, and consequently policy evaluation. In particular, endogenous quality choices introduce non-linearities into the budget constraint since the marginal return to an hour of work depends on the quality of services provided. We illustrate by considering a particular example: the recent reform in compensation contracts for specialist physicians in the province of Quebec (Canada). Prior to 1999, most Quebec specialist physicians were paid fee-for-service contracts; they received a piece rate for each clinical service provided. In 1999, the government introduced a mixed remuneration system, under which physicians received a base (half-daily or daily) wage, independent of services provided, and a reduced fee-for-service. Moreover, the government allowed physicians to choose their contract. We derive theoretical results for the effect of the reform on the quantity and quality of services supplied by analyzing "local" prices and virtual income. We propose discretizing the choice set as an empirical approach to policy evaluation in the presence of non-linear budget constraints.
[Résumé] Cet article propose un cadre à la fois empirique et théorique d'évaluation des réformes des modes de rémunération des médecins. L'accent est mis sur la nécessité de prendre en compte simultanément la qualité et la quantité des services médicaux offerts. L'introduction de la qualité modifie profondément l'analyse tant théorique qu'empirique du comportement d'offre de travail, et donc les méthodes d'évaluation. L'endogéniété du niveau de qualité engendre en particulier des non-linéarités dans la contrainte budgétaire, dans la mesure où le rendement marginal d'une heure de travail dépend de la qualité des actes fournis. A titre d'illustration, ce cadre d'analyse est appliqué à un exemple récent, la réforme du mode de rémunération des médecins spécialistes survenue au Québec (Canada) en 1999. Avant cette date, la plupart des médecins spécialistes du Québec étaient soumis à un système de rémunération à l'acte. En 1999, un système de rémunération mixte est introduit, offrant aux médecins un salaire de base (à la journée ou à la demie-journée), indépendant du volume d'actes fourni, ainsi qu'un taux de rémunération à l'acte réduit. Les médecins sont en outre laissés libres de choisir leur mode de rémunération. Les effets théoriques de cette réforme sur la quantité comme la qualité des actes fournis sont dérivés de variations locales des paramètres de rémunération. En présence de telles non-linéarités de la contrainte budgétaire, nous proposons un modèle empirique consistant à discrétiser l'ensemble de choix.
[Release notes] Earlier version: CIRPEE WP n°08-07.

Jacquemet N., Rullière J-L. Vialle, I. (2008). Monitoring optimistic agents. Journal of Economic Psychology, Vol. 29(5), pp. 698-714 [free download]

[Abstract] Monitoring is typically included in economic models of crime thanks to a probability of detection, constant across individuals. We build on recent results in psychology to argue that comparative optimism deeply affects this standard relation. To this matter, we introduce an experiment involving proper incentives that allow a measurement of optimism bias. Our experiments support the relevance of so-called comparative optimism in decision under risk. In the context of illegal activities, our results provide a guide into costless devices to undermine fraud, through well-designed information campaigns.

Replication material. Experimental instructions.

Gabuthy Y., Jacquemet N., Marchand N. (2008). Does Resorting to Online Dispute Resolution Promote Agreements? Experimental Evidence. European Economic Review, Vol. 52(2), pp. 259-282 [free download]

[Abstract] This paper presents an experiment performed to test the properties of an innovative bargaining mechanism (called automated negotiation) used to resolve disputes arising from Internet-based transactions. The main result shows that the settlement rule tends to chill bargaining as it creates incentives for individuals to misrepresent their true valuations, which implies that automated negotiation is not able to promote agreements. However, this perverse effect depends strongly on the conflict situation. When the threat that a disagreement occurs is more credible, the strategic effect is reduced since defendants are more interested in maximizing the efficiency of a settlement than their own expected profit. The implications of these results are then used to discuss the potential role of public regulation and reputation mechanisms in Cyberspace.

Replication material. Experimental instructions.

Papers in french

D. Fougère, N. Jacquemet. (2019). Inférence causale et évaluation d’impact, Economie et Statistiques, n°510-511-512 [free download] [english version].

[Résumé] Cet article décrit de manière non technique les principales méthodes d’évaluation d’impact, expérimentales et quasi-expérimentales, et le modèle statistique qui les sous-tend. Sont ensuite recensés les articles utilisant ces méthodes que la revue Economie et statistique / Economics and Statistics a publiés durant ces quinze dernières années. Dans une seconde partie sont présentées certaines des avancées méthodologiques les plus importantes récemment proposées dans ce champ de recherche. Pour finir, l’accent est mis sur la nécessité d’être particulièrement attentif à la précision des effets estimés, mais aussi sur l’obligation de répliquer les évaluations, réalisées par expérimentation ou quasi-expérimentation, en vue de distinguer les faux-positifs des effets avérés.
[Abstract: Causal Inference and Impact Evaluation] This paper describes, in a non-technical way, the main impact evaluation methods, both experimental and quasi-experimental, and the statistical model underlying them. In the first part, we provide a brief survey of the papers making use of those methods that have been published by the journal Economie et Statistique / Economics and Statistics over the past fifteen years. In the second part, some of the most important methodological advances to have recently been put forward in this field of research are presented. To finish, we focus not only on the need to pay particular attention to the accuracy of the estimated effects, but also on the requirement to replicate evaluations, carried out by experimentation or quasi-experimentation, in order to distinguish false positives from proven effects.

Jacquemet N., Luchini S., Malézieux A., Shogren J.F. (2017). L'évasion fiscale est-elle un trait de personnalité ? Une évaluation empirique des déterminants psychologiques de la « morale fiscale ». Revue Economique, Vol. 68(5), pp. 809-828 [free download].

[Résumé] Malgré un intérêt croissant pour les déterminants non monétaires des comportements fiscaux (« tax morale »), la littérature récente apporte peu d’éléments empiriques sur le lien entre les caractéristiques de personnalité reliées à la moralité et la propension à l’évasion fiscale. Or de telles mesures sont nécessaires pour comprendre les canaux de transmission des dispositifs de lutte contre l’évasion fiscale. Pour pallier cette lacune, le présent article rend compte d’une expérience en laboratoire permettant d’observer à la fois les comportements de déclaration de revenu des participants et des mesures psychologiques issues de la littérature en psychométrie : soumission à la norme, empathie affective et cognitive, et propension à ressentir la honte et la culpabilité. Ces mesures sont combinées à l’aide d’une analyse en composantes principales afin d’en extraire les facteurs indépendants. Nos résultats montrent que la décision de frauder comme son intensité sont fortement liées à l’empathie affective, l’empathie cognitive et la dimension publique de la moralité (mesurée par la soumission à la norme et la propension à la honte). La propension à ressentir la culpabilité, en revanche, est sans effet significatif. Surtout, le pouvoir explicatif global de ces mesures de moralité individuelles est relativement faible. Ce résultat va à l’encontre de l’hypothèse d’une moralité fiscale intrinsèque, et met l’accent sur l’importance du contexte institutionnel pour comprendre les comportements d’évasion.
[Abstract: Is Tax Evasion a Personality Trait?] Despite an increasing interest in the non-monetary determinants of tax behaviors (also known as tax morale), the recent literature offers few empirical elements on the link between moral personality characters and tax evasion propensity. However, such measures are necessary to understand the transmission channels of policies targeted at fighting against tax evasion. To fill this gap, this paper reports a lab experiment allowing to observe participants’ behaviors of income declaration and psychological measures from the psychometric literature: norm-submission, affective empathy, cognitive empathy, propensity to feel guilt and shame. These measures are combined through a Principal Component Analysis to extract independent factors. Results show that the decision to evade as well as its intensity are very highly related to affective empathy, cognitive empathy and public dimension of morality (measured by norm submission and propensity to feel shame). The propensity to feel guiltiness is, however, without significant effects. More importantly, the explanatory power of these individual morality measures is rather weak. This result challenges the assumption of an intrinsical tax morale and highlights the importance of the institutional context to understand evasion behaviors.

Additional content. Video: Xerfi Canal.

Loheac Y., Alia H., Bazart C., Ali Bchir M., Blondel S., Bonescu M., Bornier A., Brouard J., Chappe N., Cochard F., Flage A., Galeotti F., Hollandts X., Hopfensitz A., Jacquemet N., Le Lec F., Lefebvre M., Leplat M., Mantilla C., Mateu G., Péron G., Peterle E., Petit E., Raiber E., Rosaz J., Rozan A., Tisserand J-C., Villeval M-C, Willinger M., Zylbersztejn A., Sutan A. (2017). Mise en place d'une expérience avec le grand public : entre recherche, vulgarisation et pédagogie. Revue Economique, Vol. 68(5), pp. 941-953 [free download].

[Résumé] Nous présentons la mise en place d’une expérience lors d’un événement grand public national, de manière simultanée dans onze villes françaises, en septembre 2015. L’expérience a impliqué plus de 2 700 participants et a duré quatre heures ininterrompues. L’objectif de cet article est à la fois de fournir une feuille de route pour une éventuelle réplication et de penser à la manière dont la discipline peut être utilisée dans des terrains nouveaux (vulgarisation, pédagogie populaire, communication grand public).
[Abstract: Methodological Considerations on Implementing a Participative Experiment] We present the implementation of an economic experiment conducted simultaneously in 11 French cities, with over 2700 participants, during four uninterrupted hours, during a popular-science event held in September 2015. Our goal is both to provide a roadmap for a possible replication and to discuss how the discipline can be used in new fields (science popularization, popular education, public communication).

Additional content. Video: Nuitdeschercheurs.

Jacquemet N., Joule R-V., Luchini S., Malézieux A. (2016). Engagement et incitations : Comportements économiques sous serment. L’actualité Economique, Vol. 92(1-2), pp. 315-349 [free download] [Slides]

[Résumé] Sous l’impulsion, notamment, de l’essor de l’économie expérimentale, la littérature récente a mis en évidence un large éventail de situations dans lesquelles les incitations monétaires échouent à orienter les comportements dans le sens désiré. Ce constat conduit à rechercher des mécanismes institutionnels alternatifs, capables de se substituer aux incitations monétaires. Cet article propose une revue des travaux s’inspirant de la psychologie sociale de l’engagement afin de développer des mécanismes non monétaires susceptibles d’affecter les comportements. Ces travaux étudient une procédure d’engagement particulière : un serment à dire la vérité. Cette procédure a été appliquée avec succès (1) au problème du biais hypothétique dans la révélation des préférences pour les biens non marchands, (2) aux défauts de coordination, et (3) à la propension à dire la vérité. Pris ensemble, ces travaux confirment la capacité de mécanismes d’engagement à guider l’élaboration d’institutions non monétaires capables d’orienter efficacement les comportements économiques.
[Release notes] Revised version of BETA WP n°2014-17.

Jacquemet N., L’Haridon O., Vialle I. (2014). Marché du travail, évaluation et économie expérimentale. Revue Française d’Economie, XXIX (1), pp. 189-226 [free download].

[Résumé] L’économie comportementale et l’économie expérimentale ont connu un formidable essor au cours des dernières décennies. L’objectif de cet article est de présenter, au travers d’un cadre général d’analyse et d’exemples d’applications, l’intérêt de l’économie expérimentale pour l’évaluation des politiques publiques sur le marché du travail. L’économie expérimentale et les méthodes alternatives existantes apparaissent comme des outils d’analyse complémentaires dans l’étude des politiques publiques. En particulier, les résultats issus de l’économie expérimentale apportent un éclairage critique sur les modèles théoriques sous-jacents à l’étude des politiques du marché du travail.
[Résumé] L'existence d'une discrimination raciale à l'embauche sur le marché du travail est désormais largement documentée dans la plupart des économies occidentales. Si ce phénomène est confirmé par différentes études pour le marché du travail français, les causes et les sources en restent largement inconnues. Cet article présente les résultats d'une étude destinée à évaluer empiriquement les principales sources de discrimination à l'embauche en Île-de-France. Cette évaluation repose sur un envoi contrôlé de candidatures en réponse à des offres d'emploi postées sur des sites publics d'information. L'étude montre que la discrimination à l'embauche à l'encontre des candidats issus de l'immigration est de l'ordre de 40 % en moyenne. Cette inégalité de traitement entre candidats affecte toutes les candidatures d'origine étrangère, indépendamment de l'origine du candidat, ce qui va à l'encontre de l'hypothèse d'une défiance ciblée à l'encontre de vagues particulières d'immigration. Sur la base de ces résultats, il semble donc que la question de la discrimination se pose bien plus en termes d'opposition entre le groupe majoritaire, «autochtone», et l'ensemble des individus issus de l'immigration, qu'en termes de difficultés spécifiques propres à certains groupes. En ce sens, les résultats confirment l'existence d'une «homéophilie» ethnique sous-jacente à la discrimination - c'est à dire d'une défiance indifférenciée de la part des employeurs à l'égard de tout candidat n'appartenant pas au groupe ethnique majoritaire. Ensuite, nos résultats indiquent que les candidatures féminines sont favorisées par rapport à leurs équivalents masculins et relativement moins affectées par la discrimination d'origine. Enfin, l'inclusion d'un signal explicite d'aisance linguistique sur la moitié des envois élimine toute discrimination liée à l'origine pour les candidatures féminines. L'effet d'un tel signal est en revanche plus faible sur la discrimination opérant entre candidatures masculines.

Gabuthy Y., Jacquemet N. (2013). Analyse économique du droit et méthode expérimentale. Economie et Prévision, n°202-203, pp.121-145 [free download]

[Résumé] L’objectif de cet article est de mettre en exergue les principaux apports de la méthode expérimentale à l’analyse économique du droit. La méthode expérimentale est conçue de manière à répliquer un environnement microéconomique prédéfini et observer le comportement d’individus réels interagissant au sein de cet environnement. Les comportements observés peuvent ainsi être confrontés aux prédictions théoriques des modèles sous-jacents. Cet article vise précisément à présenter un certain nombre d’illustrations issues de cette confrontation. La présentation aborde successivement la question de la validité du théorème de Coase, l’étude de la politique de la concurrence, l’efficacité des modes de résolution des litiges et l’analyse des comportements criminels.
[Abstract: Experimental Law and Economics] We summarise the main contributions of experimental economics to the field of law and economics. Laboratory experiments are designed to replicate a microeconomic environment and to observe the behaviour of real people interacting in that environment. Theoretical predictions can then be compared with observed behaviour to assess their empirical relevance. We present a set of illustrations derived from this comparison. We review four streams of research in experimental law and economics: the Coase theorem, competition policy, the efficiency of dispute resolution mechanisms, and criminal behaviour.

Ferey, S., Gabuthy Y., Jacquemet N. (2013). L'apport de l'économie expérimentale dans l'élaboration des politiques publiques. Revue Française d’Economie, Vol. XXVIII (2), pp.155-194 [free download].

Gabuthy Y., Jacquemet N. (2007). Une évaluation expérimentale des modes électroniques de résolution des litiges Revue Economique, Vol. 58(6), pp.1309-1330 [free download] [English version].

[Résumé] Le développement très important de l’Internet et du commerce électronique s’est accompagné de l’émergence de modes électroniques de résolution des litiges. L’objectif de l’article est d’évaluer expérimentalement l’efficacité économique d’une procédure novatrice, la négociation électronique, qui intègre la technologie comme acteur actif dans le traitement des conflits : les propositions des parties sont reçues et évaluées par un logiciel informatique qui introduit un mécanisme de convergence dans la négociation et détermine les modalités d’un accord selon une règle prédéfinie. Les résultats montrent que les parties sont incitées à exploiter stratégiquement ce mécanisme de convergence afin d’accroître leurs gains, ce qui limite largement l’efficacité de la procédure. Cependant, la menace de désaccord, liée à un accroissement du degré de conflit opposant les parties, semble limiter cet effet pervers, incitant ces dernières à la conciliation. Les implications de ces résultats permettent de discuter du rôle potentiel de la régulation publique et des mécanismes de réputation dans le monde virtuel.
[Abstract: An Experimental Evaluation of Online Dispute Resolution] The extensive development of the Internet and electronic commerce has resulted in the emergence of electronic methods of dispute resolution. The aim of this paper is to experimentally evaluate the economic performance of an innovative procedure, automated negotiation, which integrates technology as an active agent in the processing of conflicts. The parties’ proposals are received and evaluated by computer software, which introduces a convergence mechanism into the negotiation process and determines the terms of an agreement according to a pre-defined rule. The results show that the parties are incentivized to strategically exploit this convergence mechanism in order to increase their gains, and that this greatly limits the effectiveness of the process. The threat of disagreement, however, associated with an increase in the degree of conflict between the parties, seems to limit this perverse effect, incentivizing the parties towards conciliation. The implications of these results allow us to discuss the potential role of public regulation and reputation mechanisms in the virtual world.]

Jacquemet N., Rullière J-L., Vialle I. (2007) Contrôle des activités illégales en présence d’un biais d’optimisme Revue Economique, Vol. 58(3), pp.555-564 [free download].

[Résumé] Le contrôle est l’un des instruments majeurs de répression des activités illégales. Cette dimension est intégrée aux analyses économiques du crime sous la forme d’une probabilité de détection et fondée seulement sur l’aversion au risque. La psychologie cognitive montre que la perception des probabilités peut elle-même varier d’un individu à l’autre. Cet article propose une analyse expérimentale de ce type d’erreur de perception, qualifiée de « biais d’optimisme », à partir d’une série de choix entre une activité légale et une activité illégale. Les traitements expérimentaux évaluent la mesure dans laquelle les modalités de contrôle peuvent, à probabilité donnée, influencer les biais d’optimisme. Les résultats suggèrent que les politiques de communication de lutte contre les activités frauduleuses doivent favoriser la perception idiosyncrasique du risque.
[Abstract: Monitoring Illegal Activities with Optimistic Bias] Although expensive, monitoring is the most efficient mean to repress a criminal activity. This is typically included in economic models of crime thanks to a probability of detection, and only based on risk aversion. According to recent results in psychology literature, the perception of this probability can however be specific to each individual. This paper experimentally investigates the existence of such errors in probabilities forecasts, often labelled “optimism bias”. The experiment relies on choices between a no risky (legal) activity and an illegal activity – randomly penalized by a fine. The experimental treatments assess whether the way the monitoring policy is announced can affect the optimism bias. The results provide a guide into costless devices to undermine illegal activities, grounded on an idiosyncratic perception of risk.

Jacquemet N. (2006). Microéconomie de la corruption Revue Française d’Economie, Vol. XX (4), pp. 118-159 [free download] [Transparents]

[Release notes] An earlier version previously circulated as La corruption comme une imbrication de contrats: Une revue de la littérature microéconomique, CREST WP n°2005-29.

Book chapters

Edo A., Jacquemet. N. (2017) La discrimination dans l’accès à l’emploi, in Repenser le modèle social: 8 nouvelles questions d'économie, P. Askenazy, D. Cohen et C. Senik (ed.), Albin-Michel.

Dumont, E., Fortin B., Jacquemet N., Shearer B. (2012). Rémunération mixte et comportement professionnel des médecins, in Le Québec économique 2011. Un bilan de santé du Québec, L. Godbout, M. Joanis et N. de Mercellis-Warin (ed.), Presses de l’Université Laval. [find the book] [download the chapter]

Jacquemet. N. (2013) Discriminations à l’embauche : quelle ampleur, quelles solutions? in Regards croisés sur l’économie, octobre 2013 Vol. 1 (13), pp. 49-63, La découverte.

Gabuthy Y., Jacquemet N. (2009). Economie expérimentale et droit, in Analyse économique du droit, Deffains B. et Langlais E. (ed.), De Boeck Universités, Collection « Ouvertures ».