When do social cues and scientific information affect stated preferences? Insights from an experiment on air pollutionDominique Ami, Frédéric Aprahamian, Olivier Chanel and Stéphane Luchini, Journal of Choice Modelling, Volume 29, Issue C, pp. 33-46, 2018

Stated preference surveys are usually carried out in one session, without any follow-up interview after respondents have had the opportunity to experience the public goods or policies they were asked to value. Consequently, a stated preference survey needs to be designed so as to provide respondents with all the relevant information, and to help them process this information so they can perform the valuation exercise properly. In this paper, we study experimentally an elicitation procedure in which respondents are provided with a sequence of different types of information (social cues and objective information) that allows them to sequentially revise their willingness-to-pay (WTP) values. Our experiment was carried out in large groups using an electronic voting system which allows us to construct social cues in real time. To analyse the data, we developed an anchoring-type structural model that allows us to estimate the direct effect (at the current round) and the indirect effect (on subsequent rounds) of information. Our results shed new light on the interacted effect of social cues and objective information: social cues have little or no direct effect on WTP values but they have a strong indirect effect on how respondents process scientific information. Social cues have the most noticeable effect on respondents who initially report a WTP below the group average but only after receiving additional objective information about the valuation task. We suggest that the construction and the provision of social cues should be added to the list of tools and controls for stated preference methods.

Stated Preferences and Decision-Making: Three Applications to HealthDominique Ami, Frédéric Aprahamian and Stéphane Luchini, Revue Économique, Volume 68, Issue 3, pp. 327-333, 2017


Willingness to pay of committed citizens: A field experimentDominique Ami, Frédéric Aprahamian, Olivier Chanel, Robert-Vincent Joule and Stéphane Luchini, Ecological Economics, Volume 105, Issue C, pp. 31-39, 2014

In this paper, we propose a behavioral approach to determine the extent to which the consumer/citizen distinction affects interpretations of monetary values in stated preferences methods. We perform a field experiment dealing with air pollution, where some (randomly selected) subjects are given the opportunity to behave politically by signing a petition for environmental protection prior to stating their private preferences in a standard contingent valuation exercise. We show that signing has the potential to influence respondents' willingness to pay values. Results indicate that even market-like situations are not immune to citizen behavior.

Comment les individus valorisent-ils les décès associés à la pollution atmosphérique ? Une comparaison de trois scénarios hypothétiquesDominique Ami, Frédéric Aprahamian, Olivier Chanel and Stéphane Luchini, Économie et Statistique, Volume 460-461, Issue 1, pp. 107-128, 2013

[fr] La valorisation économique d’une diminution du risque de mortalité recourt de plus en plus fréquemment aux techniques d’évaluation contingente. Celles‑ci consistent à interroger un échantillon d’individus sur leur «consentement à payer » (CAP) pour réduire ce risque à partir de scénarios hypothétiques. Les CAP dépendent toutefois de nombreux facteurs et notamment de la nature du risque sous‑jacent et du scénario proposé pour le réduire. Cet article s’intéresse à la diminution du risque de mortalité associé à une exposition à la pollution atmosphérique et teste l’effet d’une modification du contexte d’évaluation hypothétique à travers trois scénarios : un nouveau médicament, un déménagement et de nouvelles réglementations. Pour analyser les CAP déclarés dans les différents scénarios, nous définissons un cadre d’analyse unifié, théorique puis économétrique, qui prend en compte les préférences des participants pour le présent, ainsi que celles des autres membres du ménage. Deux résultats en découlent. Les taux d’actualisation implicites estimés, spécifiques à chacun des scénarios hypothétiques, se révèlent significativement différents. De l’ordre de 7 % pour le scénario «déménagement » , ils sont respectivement de 24 % et 26 % pour les scénarios «médicament » et «réglementation » . Il en résulte des «valeurs d’évitement d’un décès » (VED) moyennes très différentes entre le scénario «déménagement » (801 000) d’une part, et les scénarios «médicament » (299 000) et «réglementation » (252 000) d’autre part.
[en] The economic value placed on a reduction in the risk of mortality relies more and more frequently on contingent assessment techniques. These consist in questioning a sample of individuals on their “ willingness to pay” (WTP) in order to reduce this risk, on the basis of hypothetical scenarios. These WTP nevertheless depend on many factors, especially the nature of the underlying risk and the scenario proposed to reduce it. This article deals with reducing the risk of mortality associated with exposure to atmospheric pollution and tests the effect of a change in the hypothetical context of assessment through three scenarios : a new drug, a house move and new regulations. To analyse the “ willingness to pay” stated in the different scenarios, we define a unified, theoretical then econometric framework of analysis, taking into account the preferences of the participants at present, and also those of other household members. There are two main results. The estimated implicit updating rates, specific to each hypothetical scenario, were seen to differ significantly. They were about 7% for the “ move” scenario and 24% and 26% for the “ drugs” and “ regulations” scenarios respectively. Results showed that the average “ values set for avoiding death” differed greatly between the “ move” scenario (801,000) on the one hand, and the “ drugs” (299,000) and “ regulations” (252,000) scenarios on the other hand.

A Test of Cheap Talk in Different Hypothetical Contexts: The Case of Air PollutionDominique Ami, Frédéric Aprahamian, Olivier Chanel and Stéphane Luchini, Environmental & Resource Economics, Volume 50, Issue 1, pp. 111-130, 2011

We explore the influence of a neutral cheap talk script in three typical scenarios used in the CV literature devoted to the valuation of air pollution effects. We show that cheap talk has a differentiated effect depending on the scenario implemented. It decreases protest responses with no effect on WTP values in the scenario based on a new drug. When a move to a less polluted city is involved, it has no effect on protest responses but decreases WTP values. Surprisingly, cheap talk increases protest responses but decreases WTP values when new regional air pollution regulations are at stake.

Heterogeneous anchoring and the shift effect in iterative valuation questionsFrédéric Aprahamian, Olivier Chanel and Stéphane Luchini, Resource and Energy Economics, Volume 30, Issue 1, pp. 12-20, 2008

In this article, we consider starting point bias as a heterogeneous phenomenon, that is, respondents in CV surveys do not anchor in the sameway. We study the consequences of a mistaken assumption of homogeneous anchoring for the analysis of the shift effect in multiple-bounded dichotomous choice format, when respondents really have heterogeneous anchoring. We show that the shift effect, generally interpreted as incentive incompatibility or “yea”-saying, can be the spurious outcome of disregarded heterogeneous anchoring.

MicroéconomieFrédéric Aprahamian, André Bertrand, Damien Besancenot, Jean-Baptiste Ferrari and Kim Huynh, Grand Amphi, 2007, 384 pages, Bréal, 2007

Cet ouvrage présente à la fois l'essentiel des connaissances à acquérir et les apports méthodologiques indispensables. Chaque chapitre comporte une partie " cours " et une partie " applications " : QCM, exercices, documents et questions de réflexion.

AJAE Appendix: Modeling Starting Point Bias as Unobserved Heterogeneity in Contingent Valuation Surveys: An Application to Air PollutionFrédéric Aprahamian, Olivier Chanel and Stéphane Luchini, American Journal of Agricultural Economics Appendices, Volume 89, Issue 2, pp. 533-547, 2007

The material contained herein is supplementary to the article named in the title and published in the American Journal of Agricultural Economics, May 2007, Volume 89, Issue 2.

Consommation privée, dette publique et structure à terme des taux d'intérêt. L'exemple de la France et de l'ItalieFrédéric Aprahamian and Alain Paraponaris, Revue Économique, Volume 49, Issue 3, pp. 687-698, 1998

[fre] Cet article cherche à évaluer la manière dont les ménages réagissent dans leur plan de consommation aux variations de la dette publique et du niveau des impôts auxquels ils sont soumis. Les résultats obtenus à partir de variables trimestrielles sur les pays du G7 au cours des dernières décennies montrent, à l'instar de Dalamagas [1993], que plus le ratio dette/PIB est important, moins l'illusion de la dette et l'illusion fiscale sont fortes. Une illustration est donnée pour la France et l'Italie. [eng] This paper is aimed at assessing households ability to counterbalance changes in the stock of government bonds and in the tax level in their consumption schemes. Empirical findings on quarterly data from G7 countries over the last decades establish in the fashion of Dalamagas (1993) that the bigger the debt/ GDP ratio is, the slighter the debt illusion and fiscal illusion are likely to be. Evi­dence is given for France and Italy.