Roberta Raffaelli | University of Trento (original) (raw)

Papers by Roberta Raffaelli

Does Prelec Bayesian Truth Serum prevent Social Desirability Bias in Choice Experiments

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In the context of choice experiments (CE), for example, respondents show the tendency to misrepresent their true preferences in the attempt to please the researcher and to provide socially desirable answers. This tendency, known as social desirability bias (SDB), is pervasive and has been found to occur in many types of self-reporting measures and across the social science literature (see e.g., Fisher, 1993; King and Bruner, 2000; Leggett et al., 2003; Nederhof, 1985; Fisher and Katz 2000). If not properly addressed, the problem of SDB can have important negative economic and policy implications. Given its pervasiveness and relevance, it is not surprising to see a sizable body of literature investigating alternative approaches aiming at minimizing or circumventing the SDB problem. Within the range of proposed solutions to attenuate SDB in CE, the use of actual payments (to increase the saliency of the task), SDB specific cheap talk scripts as well the use of social desirability scales to correct for SDB were shown to be unsatisfactory (e.g., Norwood and Lusk 2011). The current state of the art in dealing with SDB in CE is represented by the use of indirect questioning (or inferred questioning or inferred valuation task) (IQ), where respondents are asked to predict the behavior of others (instead of their own). The idea behind IQ is that, as people have no immediate experience of other's private information, their answers are based on their own preferences and valuations, which are adjusted for perceived differences between the person and the others. The responses to IQ are therefore correlated with one's preference and are believed to be closer to actual preferences than the responses to direct questions (Fisher 1993). IQ has recently been implemented by Lusk and Norwood (2009), Lusk and Norwood (2010) and by Carlsson et al. (2010). A new (and in the context of CE yet untested) mechanism to prevent SDB which includes the IQ is the Bayesian Truth Serum (BTS) developed by Prelec (Science 2004) and recently discussed as credible and persuasive incentive to tell the truth (Weaver and Prelec 2013). This mechanism consists of an information-scoring system that allows the researcher to reward the respondents for "truthful" answers and can be employed in eliciting subjective information (e.g., opinions, tastes, past behavior) in situations where the objective truth is intrinsically or practically unknowable. The key idea behind BTS is to assign a high score to an answer whose actual frequency is greater than its predicted frequency, with predictions drawn from the same population that supplies the answers. This complex scoring mechanism is not revealed to the respondents whose attention is instead drawn to the fact that their answers (to both direct and indirect questions) will be evaluated as being "truthful" and "accurate" according this new scientific method. Each respondent is requested to provide a personal answer (the equivalent of a direct question) and an estimate of how other respondents will answer the same question (the equivalent of an IQ). Both (direct and indirect) answers are scored to produce an aggregate score. As Prelec (2004) states, the scoring system transforms a survey into a competitive, zero-sum contest, in which truth-telling is a strict Bayesian Nash equilibrium. Our study represents the first application of the BTS in the context of CE to elicit preferences for ethical and moral attributes. We run a CE with a random sample of 800 customers of an organic store chain in three different large cities in Italy (Rom, Milan, Palermo). The product used in the CE is organic pasta, a staple in Italian cuisine. The pasta attributes considered in the CE include several normative dimensions (e.g., fair price to producers, environmentally-friendly production, social responsible workforce etc). Data was collected at the grocery store using touch-screen computer assisted face-to-face interview. All respondents were faced with a set of direct and a set of indirect questions. The direct questions (6 choice cards) asked consumers to select…

Indirect questioning as a nudging instrument? Evidence from a CE

International Choice Modelling Conference 2017, Mar 28, 2017

Indirect questioning (IQ), where respondents are asked to predict the behavior of others (instead... more Indirect questioning (IQ), where respondents are asked to predict the behavior of others (instead of their own), has been used in surveys since the ’70 in order to elicit private information about sensitive issues. The idea behind IQ is that, as people have no immediate experience of other’s private information, their answers are based on their own attitudes, intentions and behaviour, which they adjust for perceived differences between themselves and others. Therefore, the responses to IQ are believed to be less prone to social desirability bias and demand effects (Fisher 1993). Recently indirect questioning (called also inferred valuation IV) has been implemented in choice experiments as a mechanism to remove social desirability bias in preference elicitation (Lusk and Norwood (2009), Lusk and Norwood (2010), Carlsson et al. (2010), Olynk, Tonsor, and Wolf (2010), and Yadav et al (2013). This approach rests on the assumptions that respondents do not derive utility from misrepresenting someone else’s preference and respondents reveal their own preferences with their predictions. IQ have been employed by using different question formats (e.g. asking to predict the choice of an “average person” or to predict the distribution of choices of others), with and without monetary incentives, with different degree of scrutiny by the interviewers (online vs face-to-face at home), adopting both the between subject and with-in subjects approach. Substantial evidence has been collected that indeed shows WTP measures obtained with inferred valuation are lower than those obtained with direct questions (instilling confidence that IQ contribute to the removal of social desirability bias), nevertheless it is unclear how well inferred valuation WTP measures reflect real preferences. Some findings of recent stated preference studies and insights from the social psychology literature suggest the presence of potential issues with IQ. First, the study by Carlsson et al. (2010) suggests that IQ (and not only direct questions) might be subject to a self-enhancement effect when respondents attempt to present themselves in a relatively favorable light by distorting the predictions of others’ preferences or behavior. Second, ample evidence from social psychology suggests that people think of themselves as ‘better’ than others, the so-called ‘better-than-average’ effect (Alicke & Govorun 2005). In either case, estimates obtained with IQ might be downwardly biased. Third, the stated preference literature has used a wide range of different behaviors to be predicted with IQ, without critically assessing the effect of these differences on elicited values. For example, in some studies respondents were asked to predict others’ behavior in a real market situation (e.g., at the grocery store), and in other studies respondents were asked to predict others’ behavior in hypothetical situations (e.g., hypothetical product choices of study participants). While one might expect the specific behavior which is to be predicted to affect the elicited values, to the best of our knowledge no explicit discussion of this issue can be found in the literature. Our study investigates all these issues related to the use of IQ with a CE designed to elicit preferences for organic pasta characterized by normative attributes concerning the origin, cultivar, and the production and processing conditions (e.g. fair price to producers and social responsible workforce). We used a partial within-subject and partial between-subject experiment design with two question formats (direct and indirect questions), three treatments ((i) with incentives to provide accurate estimates of others’ purchase intentions, (ii) with incentives to provide accurate estimates of others’ actual purchase, and (iii) without incentives (control treatment)), and two order of presentation regarding the format of the questions (direct questions first or indirect questions first). As an economic incentive we used store coupons of the value of 30 Euros granted to the best predicting respondents. Data was collected at an organic store chain in three different large cities in Italy (Rom, Milan, Palermo) using touch-screen computer assisted face-to-face interview. A random sample of 600 respondents faced 6 choice cards with 3 alternatives plus the no-buy option. Choice cards were presented twice: once in the form of the traditional direct question (pick one) and once in the form of an indirect question asking respondents to make predictions of the answers/choices of a sample of store’s customers participating in the study. Order of presentation was randomized. The results are very interesting. Apart from the expected results of IQ leading to lower WTPs than direct questioning for normative attributes, we find no evidence that answers to IQ are affected by a significant indirect self-enhancement effect. Only in a few cases, we find evidence that respondents hold downward biased beliefs regarding others.…

A reflection on the technical barriers to trade in food products; the case of meat trade between the EC and Canada

Stated attribute cut-offs in choice experiments: do they affect the variance of choices?

International Choice Modelling Conference 2013, May 14, 2013

Are tourists willing to pay for decarbonizing tourism? Two applications of indirect questioning in discrete choice experiments

Journal of Environmental Planning and Management, 2021

The feasibility and efficiency of public policies aimed at decarbonizing tourism also depend on t... more The feasibility and efficiency of public policies aimed at decarbonizing tourism also depend on tourists’ attitudes and acceptance. This paper investigates tourists’ preferences and willingness to pay (WTP) for decarbonizing strategies applied to transportation and hotel accommodation. Two discrete choice experiments were conducted in the Dolomites area in Italy using direct and indirect question formats. The combination of question formats is proposed as an instrument to reduce hypothetical bias and obtain conservative WTP-range estimates. Results suggest low to zero willingness to pay for the two key attributes: the use of electric trains that produce lower amounts of carbon emissions and the possibility to offset the carbon emissions associated with tourists’ hotel stays. These results indicate the need for new policy interventions to promote forms of public-private partnerships to support public and private investments, increase tourists’ awareness of decarbonizing strategies and foster a move toward more sustainable behaviors.

Consumers' attitude to fruit produced by using biocontrol agents and climate change mitigation practices

Concerns for potential risks related to the use of chemical pesticides have encouraged research o... more Concerns for potential risks related to the use of chemical pesticides have encouraged research of low impact alternatives as biocontrol agents (BCAs) and the implementation of a more environmentally sound agricultural management as the integrated pest management (IPM) and organic agriculture. A new regulation was recently implemented in the European Union (EC No 834/2007), which establishes the legal framework for all levels of production, distribution, control and labelling of organic products. Most of the European consumers are now familiar with IPM and organic products. Climate change is becoming a hot issue and mitigation practices are under discussion in agriculture, too. The level of consumers’ awareness of mitigation practices and their willingness to pay for products produced with low carbon emission is unknown. Consumers’ attitudes and preferences to fruit (apples) produced by using BCAs instead of chemical pesticides and/or climate change mitigation practices were evaluated in a choice experiment. Preference for other apple determinants such as origin, appearance and price were also considered. The survey was administered to 96 consumers in different supermarkets in Northern Italy during fall 2009. Results show that in purchase decision, origin and price are the major determinants, followed by organic production and good appearance. Using BCAs and climate change mitigation practices increased the probability of purchasing apples. However, only coefficient associated to climate change is statistically significant and respondents are willing to pay a premium price of about 0.50 Euro/kg. Moreover, results indicate that when buying apples most people have specific requirements in mind regarding method of production, origin, appearance and price, but comparing choices made by the respondents with their individually-stated minimum requirements, the majority violated the

Indirect questioning as a nudging instrument? Evidence from a CE

Modelling the effects of stated attribute non-attendance on its inference: an application to visitors benefits from the alpine grazing commons

Attribute non-attendance (ANA) in choice experiments has recently been the subject of much invest... more Attribute non-attendance (ANA) in choice experiments has recently been the subject of much investigation. There is no general agreement about the magnitude and direction of the effects of non-attendance but most studies conclude that ANA matters in applied choice analysis for policy purposes. Two approaches have been used so far to identify and quantify attribute non attendance, namely respondent-reported non-attendance and analytical (or inferred) non-attendance. The consistency between self-reported ANA and ANA inferred by statistical models is not yet resolved. The present study aims at testing the internal consistency of inferred non-attendance from different stages of a rank-ordered best/worst elicitation method and at teasing out drivers of non-attendance in full rank-ordered data. The empirical dataset comes from a multi-attribute stated choice survey carried out in 2008 in the province of Trento (North East Italy) aiming at estimating willingness to pay for access to the Alp...

Estimating risk preferences integrating insurance choices with subjective beliefs

European Economic Review, 2021

Subjective probabilities, scientific information and food choices: A test of scenario adjustment in choice experiments

Valuing the external effects of Alpine transhumance: an application of the best-worst approach to rank-ordered data

In many environmental valuation applications standard sample sizes for choice modelling surveys a... more In many environmental valuation applications standard sample sizes for choice modelling surveys are impractical to achieve. One option to improve data quality is to use more in-depth surveys conducted on fewer respondents. This is certainly the case for studies on mountain visitation. We report on a study using high quality rank-ordered data in which the ranking of alternatives is elicited by means of the best-worst approach to alternative selection. The resulting exploded choice model involved the collection of 64 responses per person which were used to study the willingness to pay for external benefits produced to visitors by policies keeping in place the artefacts of alpine transhumance. The context of study is Val di Genova, a valley with summer pastures located in the North Eastern Alps where we study visitors WTP for pasture landscape, biodiversity, historical heritage and the up-keep of in-situ milk transformation. We find good evidence in support of this approach and find re...

Costs and benefits of multifunctional Alpine pasture: a case study

Are we standard or non-standard expected utility maximizers? Discrete mixture models of choice over food-safety policies with risky outcomes

The effect of good and bad news on preferences: A discrete choice model of reductions in pesticide residue risk

Policies to improve food safety are often highly uncertain. Public support for a policy then will... more Policies to improve food safety are often highly uncertain. Public support for a policy then will generally depend on how people process information about risky outcomes on the basis of their probabilistic beliefs. We implement a discrete choice experiment where each alternative is featured as a binary lottery, and test whether respondents fully revise their probabilistic beliefs to conform with information given to them in the opt-out alternative. We also explore whether respondents’ updating behavior depends on whether information is perceived as a good or bad news. Fechner models that take the form of parametric non-linear mixed logit models are used to investigate preferences for risk and time, and to estimate option prices. Our analyses show that while presented good news is fully accepted by respondents, the bad news is not. Asymmetric updating influences welfare measures and we show that ignoring this phenomenon results in overestimation of estimated option prices.

Global climate change and sustainable management of agriculture in a highly developed mountain environment

IOP Conference Series: Earth and Environmental Science, 2009

ABSTRACT This article was submitted without an abstract, please refer to the full-text PDF file.

Exploring the consistency of alternative best and/or worst ranking procedures

Ipotesi di valorizzazione delle risorse demaniali in un’ottica di fruizione turistico ricreativa sostenibile. Il caso della Provincia di Trento

Department of Economics Working Papers, 2008

The aim of this paper is to take stock of the situation regarding the main types of damage to for... more The aim of this paper is to take stock of the situation regarding the main types of damage to forests and their respective economic consequences, with reference to a case study in the Italian Alps (Trentino province). Each kind of damage (wind and snow, defoliation, fire and tillage) has been analysed in terms of its impact on four forest functions (production, protection, tourism-recreation and carbon sequestration) and evaluated in monetary terms. Market value was used to estimate the production and carbon sequestration functions, replacement cost method for protection, and contingent valuation for tourism-recreation. Applying desk research on damage caused by the main biotic and abiotic factors to this particular case study led to estimate a annual damage of about € 1,633,595 equal to € 4.73 per hectar. This can be considered a lower bound estimate of possibly greater damage. Another interesting result emerged from the evaluation exercise is that the wealth of information produced through monitoring and scientific research in the last twenty years does not readily lend itself to economic analysis.

Testing hypothetical bias with a real choice experiment using respondents' own money

European Review of Agricultural Economics, 2013

ABSTRACT The investigation of hypothetical bias in choice experiments (CEs) has typically been co... more ABSTRACT The investigation of hypothetical bias in choice experiments (CEs) has typically been conducted in the laboratory with only minimal field experiments. Moreover, it is common practice to provide an initial endowment (money or coupons) to respondents. In this research, we employed a between-subject CE in a supermarket with three different treatments (i.e. hypothetical, hypothetical with cheap talk script and real). With the ‘real’ treatment, we required respondents to use their own money when making a payment. The proposed incentive-compatible mechanism mimics as close as possible the everyday purchasing situation. Results confirm the presence of hypothetical bias and the mixed effectiveness of a cheap talk script.

Risk Aversion, Subjective Beliefs, and Farmer Risk Management Strategies

American Journal of Agricultural Economics, 2012

Building upon early theoretical work that established the underlying principles of deci-sion maki... more Building upon early theoretical work that established the underlying principles of deci-sion making in settings involving risk (e.g. Arrow 1965; Pratt 1964; Von Neumann and Morgenstern 1944), a substantial body of experimental literature has developed inves-tigating the theory of risk in laboratory and field settings in order to better understand agent behavior and market outcomes. These experimental explorations are motivated by the ubiquity of risk across the spectrumof deci-sions that agents make on a daily basis. In agricultural production, where farmers ’ yields and revenue are dependent upon numerous largely exogenous factors such as weather conditions and price fluctuations, risk and uncertainty is omnipresent in farming deci-sions. Ultimately, risk and uncertainty influ-ence crop-selection and crop-rotation schemes (El-Nazer andMcCarl 1986), technology adop-tion (Purvis et al. 1995), environmental degra-dation and policy compliance (Ozanne,Hogan, andColman2001),andcrop insurancemarkets. Early experimental studies focusing on deci-sion making under uncertainty revealed that