The ABC mechanism: an incentive compatible payoff mechanism for elicitation of outcome and probability transformations

When it comes to experiments with multiple-round decisions under risk, the current payoff mechanisms are incentive compatible with either outcome weighting theories or probability weighting theories, but not both. In this paper, I introduce a new payoff mechanism, the Accumulative Best Choice (“ABC”) mechanism that is incentive compatible for all rational risk preferences. I also identify three necessary and sufficient conditions for a payoff mechanism to be incentive compatible for all models of decision under risk with complete and transitive preferences. I show that ABC is the unique incentive compatible mechanism for rational risk preferences in a multiple-task setting. In addition, I test empirical validity of the ABC mechanism in the lab. The results from both a choice pattern experiment and a preference (structural) estimation experiment show that individual choices under the ABC mechanism are statistically not different from those observed with the one-round task experimental design. The ABC mechanism supports unbiased elicitation of both outcome and probability transformations as well as testing alternative decision models that do or do not include the independence axiom.

     

Response Strategies and Learning in Discrete Choice Experiments

This study explores ordering effects and response strategies in repeated binary discrete choice experiments. Mechanism design theory and empirical evidence suggest that repeated choice tasks per respondent induce strategic behaviour. We find evidence that strategic opportunities provided by the order in which choice sets are presented to respondents affect choice decisions (strategic response). The results suggest, however, that respondents may solely respond to high cost rather than low cost inconsistencies. That is, respondents are more cost sensitive, and thus have a lower willingness to pay (WTP), if the same or a similar level of provision was offered in a previous choice set at a lower cost than if it was not. Yet, the cost sensitivity, and thus WTP, remains unaffected if the same or a similar level of provision was offered in a previous choice set at a higher cost. Our findings further indicate that cost sensitivity increases (and thus WTP decreases), when respondents progress through the choice task, with this increase (decrease) lessening as more choice questions are answered. Possible explanations are value learning and strategic learning.     

Choice Certainty and Consistency in Repeated Choice Experiments

The main objective of this study is to examine how repeated choice affects preference learning in stated preference experiments. We test different hypotheses related to preference learning by analyzing response patterns and asking respondents in a choice experiment to report their experienced certainty when going through the choice tasks. In a split-sample test, we show that follow-up choice certainty questions are procedural invariant. The self-reported certainty results indicate that learning occurs, but econometric testing procedures do not identify any significant impact of learning effects on parameter estimates or variance across choice tasks. Additional tests of choice consistency suggest that preferences in the choice experiment are stable and coherent.     

Salt or Sludge? Exploring Preferences for Potable Water Sources

Decision makers often use information about public preferences to guide public policy. Several disciplines gather information on preferences through surveys by asking respondents to make hypothetical choices over potential policies. However the context of the choice question differs between approaches, with some failing to make the full consequences of the respondent’s choice explicit in the question. In this study we investigate whether question context matters, by exploring whether economic and psychology approaches yield a similar understanding of community preferences towards a large-scale recycled wastewater scheme. We find that stated preferences differ depending on whether the preference question is contextualised using economic incentives. The findings provide insight into the implications of inappropriately contextualised preference questions, methodological considerations in attitude identification and estimation, and the diversity of values and public attitudes towards recycled wastewater.     

Theoretical incentive properties of contingent valuation questions: Do they matter in the field?

Green et al. (1998) [Green, D., Jacowitz, K.E., Kahneman, D., McFadden, D., 1998. Referendum contigent valuation, anchoring, and willingness to pay for public goods. Resource and Energy Economics 20 (2), 85−116] show theoretically that stated preference questions about public services can be framed in such ways that if the subjects accept the frame the payoff­maximizing behavior will be to answer truthfully. One key element of such a theoretically incentive­compatible framing is that the (hypothetical) decision rule specified in the survey instrument is understood to be a majority rule rather than the efficiency rule typically used in cost­benefit analysis. We conducted field experiments in Germany and Switzerland to test if a referendum framing as suggested by Green et al. is effective in reducing strategic misrepresentation in a contingent valuation setting. We did not find the expected effects of the framing treatments on stated willingness to pay or on individuals' (stated) beliefs about the social choice context. The results do not support hopes that a theoretically incentive compatible framing could be purposefully used to invoke the specific beliefs about the linkage between responses and policy implementation that would make stated preference questions incentive compatible.     

Position-Dependent order effects on the prediction of consumer preferences in repeated choice experiments

Using stated choice data collected by experimental design with repeated choice tasks, this study developed an approach to quantify the position-dependent order effects on the prediction of preferences and marginal willingness to pay for product attributes. Results showed that repeated choice tasks allow learning to occur. Models with order effect adjustments showed significant improvements in goodness of fit. Attribute-specific polynomial trends showed the best fit among all models, which could possibly be explained by respondents’ familiarity and sensitivity to different product attributes. Repeated-choice experiments have a good potential to capture consumer preferences more accurately than the single-choice design. But order effects need to be taken into account for preferences and market prediction.     

Robustness of simple menus of contracts in cost-based procurement

We consider a model of cost-based procurement in which the principal faces Knightian uncertainty about the agent's preferences for cost reduction. We show that a particularly simple incentive scheme—a menu comprising a fixed-price contract and a cost-reimbursement contract—minimizes the maximum expected payment, where this maximum is taken over the set of possible agent preferences. For some parameters of the problem, a range of alternative incentive schemes also satisfy this criterion. We show that the simple incentive scheme is not weakly dominated by any of the alternatives: there does not exist an alternative mechanism for which the expected payment is no higher for all realizations of the agent's preferences and strictly lower for some realization.     

Accounting for Preference and Scale Heterogeneity in Establishing Whether it Matters Who is Interviewed to Reveal Household Automobile Purchase Preferences

The choice of automobile purchases in households often involves participation of more than one household member, each of which exerts some degree of influence on the final choice outcome. The influence of more than one agent has been recognised for many years, and yet the majority of automobile choice studies develop choice models as if a single agent is involved in the preference revelation process. What is not clear is whether it makes any substantive difference in preference revelation according to who is interviewed in a household. Using a generalised mixed logit framework that accounts for preference and scale heterogeneity, we estimate a series of models to investigate whether there are significant differences between the preferences of each individual in a household when assessed in isolation from other household members, as well as their joint preferences when expressing their preferences through a group choice task. The context is choosing amongst petrol, diesel and hybrid fuelled vehicles (associated with specific levels of fuel efficiency and engine capacity) when faced with a mix of vehicle prices, fuel prices, fixed annual registration fees, annual emission surcharges and vehicle kilometre emission surcharges. Using a stated choice experiment, we find that sampling a single individual as a representative of the household’s preferences is less appropriate than utilising preference information from the relevant group of decision makers in the household.     

Fully sincere voting

In a general social choice framework where the requirement of strategy-proofness may not be sensible, we call a social choice rule fully sincere if it never gives any individual an incentive to vote for a less-preferred alternative over a more-preferred one and provides an incentive to vote for an alternative if and only if it is preferred to the default option that would result from abstaining. If the social choice rule can depend only on the number of votes that each alternative receives, those rules satisfying full sincerity are convex combinations of the rule that chooses each alternative with probability equal to the proportion of the vote it receives and an arbitrary rule that ignores voters' preferences. We note a sense in which the natural probabilistic analog of approval voting is the fully sincere rule that allows voters maximal flexibility in expressing their preferences and gives these preferences maximal weight.     

Fully sincere voting

In a general social choice framework where the requirement of strategy-proofness may not be sensible, we call a social choice rule fully sincere if it never gives any individual an incentive to vote for a less-preferred alternative over a more-preferred one and provides an incentive to vote for an alternative if and only if it is preferred to the default option that would result from abstaining. If the social choice rule can depend only on the number of votes that each alternative receives, those rules satisfying full sincerity are convex combinations of the rule that chooses each alternative with probability equal to the proportion of the vote it receives and an arbitrary rule that ignores voters' preferences. We note a sense in which the natural probabilistic analog of approval voting is the fully sincere rule that allows voters maximal flexibility in expressing their preferences and gives these preferences maximal weight.     

Modelling Heterogeneity in Response Behaviour Towards a Sequence of Discrete Choice Questions: A Probabilistic Decision Process Model

There is a growing body of evidence in the non-market valuation literature suggesting that responses to a sequence of discrete choice questions tend to violate the assumptions typically made by analysts regarding independence of responses and stability of preferences. Decision processes (or heuristics) such as value learning and strategic misrepresentation have been offered as explanations for these results. While a few studies have tested these heuristics as competing hypotheses, none has investigated the possibility that each explains the response behaviour of a subgroup of the population. In this paper, we make a contribution towards addressing this research gap by presenting a probabilistic decision process model designed to estimate the proportion of respondents employing defined heuristics. We demonstrate the model on binary and multinomial choice data sources and find three distinct types of response behaviour. The results suggest that accounting for heterogeneity in response behaviour may be a better way forward than attempting to identify a single heuristic to explain the behaviour of all respondents.     

Robust Implementation in Direct Mechanisms

A social choice function is robustly implementable if there is a mechanism under which the process of iteratively eliminating strictly dominated messages lead to outcomes that agree with the social choice function for all beliefs at every type profile. In an interdependent-value environment with single-crossing preferences, we identify a contraction property on the preferences which together with strict ex post incentive compatibility is sufficient to guarantee robust implementation in the direct mechanism. Strict ex post incentive compatibility and the contraction property are also necessary for robust implementation in any mechanism, including indirect ones. The contraction property requires that the interdependence is not too high. In a linear signal model, the contraction property is equivalent to an interdependence matrix having all eigenvalues smaller than one.     

Temporal stability of preferences and willingness to pay for natural areas in choice experiments: A test–retest

The main objective of this paper is to test the temporal stability of stated preferences and willingness to pay (WTP) values from a Choice Experiment (CE) in a test–retest. The same group of participants was asked the same choice tasks in an internet-based CE, conducted twice with a time interval of one year without interviewer interference. We examine choice consistency at individual choice task level and transferability of the underlying indirect utility function and associated WTP values. The results show that choices are consistent in 57 percent of the choice occasions. Comparison of the choice models over time shows that the estimated preference and scale parameters are significantly different, suggesting that choice behaviour changed between the two surveys. Differences between marginal WTP estimates for individual choice attributes are statistically significant only at the 10 percent level. However, we show that this can result in significantly different WTP values for policy scenarios. The instability of estimated mean WTP values for different policy scenarios asks for caution when including WTP values in cost-benefit analysis.     

Assessing information provision and respondent involvement effects on preferences

We develop a test of the effect of information and respondent involvement on preferences for passive-use values using three treatments. Individuals from a rural community participated in one of three groups, each with a different level of involvement in the valuation assessment. The first group was highly involved, attending three meetings which allowed for information acquisition and preference construction. The second group was involved in a single meeting, and the third group was minimally involved through telephone contact and the completion of a mail administered survey. The hypothesis examined was that the degree of involvement in the exercise would affect the magnitude and consistency of preferences across the groups. The hypothesis that the preferences differ was not accepted. Furthermore, the hypothesis that variances in preferences would be higher in less involved groups was also rejected. While the analysis is based on relatively small samples the findings suggest caution in claiming that increasing degrees of respondent involvement improve economic measures of trade-offs.     

Endogenous buyer-seller choice and divisible money in search equilibrium

In the Lagos-Wright model [R. Lagos, R. Wright, A unified framework for monetary theory and policy analysis, J. Polit. Economy 113 (2005) 463-484], the quasi-linear preferences assumption is not necessary to generate simple distributions of money holdings if individuals choose endogenously to go to the search market as buyers or as sellers. The non-convex buyer-seller choice provides an incentive for gambling in lotteries, and, as a result, the value function has a linear interval. As long as this interval is the relevant one for evaluating their future utilities, individuals behave as if their preferences were quasi-linear. In the stationary equilibrium, individuals remain inside this linear interval if the money supply does not decline.     

Respondent uncertainty in a contingent market for carbon offsets

The main objective of this paper is to provide additional empirical evidence of what explains respondent uncertainty in contingent valuation (CV) and how this in turn affects stated willingness to pay (WTP). Air travelers asked to pay a carbon travel tax to offset carbon emissions from flying were asked how likely it is that they will actually pay if the tax is voluntary. When changing the market compliance imperative from a mandatory carbon tax to a voluntary contribution, a third of all air travelers consider it unlikely they will actually pay their stated WTP amount. An ordered probit estimation approach is applied to identify the sources of respondent uncertainty. Besides the bid price, respondent sense of responsibility and belief in the effectiveness of the voluntary carbon market are among the main reasons for the experienced uncertainty.     

Incorporating Discontinuous Preferences into the Analysis of Discrete Choice Experiments

Data from a discrete choice experiment on improvements of rural landscape attributes are used to investigate the implications of discontinuous preferences on willingness to pay estimates. Using a multinomial error component logit model, we explore differences in scale and unexplained variance between respondents with discontinuous and continuous preferences and condition taste intensities on whether or not each attribute was considered by the respondent during the evaluation of alternatives. Results suggest that significant improvements in model performance can be achieved when discontinuous preferences are accommodated in the econometric specification, and that the magnitude and robustness of the willingness to pay estimates are sensitive to discontinuous preferences.     

A Meta-study Investigating the Sources of Protest Behaviour in Stated Preference Surveys

It is a well-known empirical finding that some percentage of respondents participating in Stated Preference surveys will not give responses that reflect their true preferences. One reason is protest behaviour. If the distribution of protest responses is not independent of respondent or survey characteristics, then simply expelling protesters from surveys can lead to sample selection bias. Furthermore, WTP estimates will not be comparable across surveys. This paper seeks to explore potential causes of protest behaviour through a meta-study based on full datasets from 38 different surveys. The objective of the study is to examine the effect of respondent specific variables as well as survey specific variables on protest behaviour. Our results suggest that some of the differences in WTP typically observed between different demographic groups, different elicitation formats and different question formats might actually be attributed to inherent differences in the propensity to protest. Our results indicate that the propensity for respondents to exhibit protest behaviour when asked a stated preference type valuation question depends on a number of specific factors, respondent specific as well as survey specific—knowledge which could be used in order to reduce protest behaviour.     

Exchange Rules and the Incentive Compatibility of Choice Experiments

The incentive properties of stated-preference surveys continue to be a central debate in the valuation of public goods. The majority of empirical studies have focused on incentive properties of contingent valuation questions in relation to situations where answers have monetary consequences. This research explores the incentive properties of repeated, attribute-based choice questions when subjects are provided with an explicit connection between choices and outcomes. Two market/provision-rules are investigated: a posted-price market and a plurality-rule vote. These two provision rules are contrasted to treatments in which no provision rule is discussed—subjects are simply asked to choose their preferred alternative. These three hypothetical choice treatments are compared with a binding choice treatment. While none of the public good treatments are theoretically incentive compatible, we include a comparison of hypothetical and binding choices for a private-good that is incentive compatible. The private good experiments indicate that marginal willingness to pay (WTP) estimates from the hypothetical treatment are larger, but not statistically different than corresponding estimates in the binding choice treatment. Results for the public good experiments indicate that marginal WTP estimates from the hypothetical treatments are much larger, and statistically different than corresponding estimates in the binding choice treatment. The bias is largest when no provision rule is discussed. The bias is reduced with the inclusion of a provision rule, but surprisingly, there was no difference across provision rule treatments. Overall, our results indicate that choice experiments involving a public good should include a provision rule to reduce bias, but the resulting marginal WTP estimates may still be more biased, on average, than those arising from contingent valuation survey formats.