Do People Always Pay Less Than They Say? Testbed Laboratory Experiments with IV and HG Values

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.     

Demand Revelation,Hypothetical Bias,and Threshold Public Goods Provision

We examine the issues of hypothetical bias, demand revelation, and gender differences in a threshold public goods experiment with heterogeneous induced-values. First, we find no evidence of hypothetical bias in our threshold provision public goods experiments, despite the fact this is an open-ended type mechanism. Our results support recent experimental findings that use induced-values to investigate hypothetical bias. Second, we investigate the demand revealing performance of real and hypothetical payments and find no evidence that real payment performs better than hypothetical payment in our experiments. Third, we examine whether payments, real and hypothetical, are positively related to induced-values. Our results suggest there is statistical evidence that payments are positively related to true values. Finally, we examine the effect of gender on real and hypothetical payments in our experiment. The results show that gender matters for contributions through both real and hypothetical payments, after controlling for true values as well as socio-economic variables. Results also indicate that females are more likely to truthfully reveal their value than males through hypothetical payments, but gender is not significant for truthfully revealing their value through real payments.     

Hypothetical Bias in Risk Preferences as a Driver of Hypothetical Bias in Willingness to Pay: Experimental Evidence

This study provides new insight on the established issue of elicitation bias in hypothetical choice settings. In particular, using an experiment that elicits real and hypothetical willingness to pay for the protection of otters, we provide evidence that the observed bias is driven by those who are both uncertain about their value and exhibit hypothetical bias in risk attitudes. This finding provides a reason why calibration approaches based on follow-up certainty questions have proven useful, but also suggests a degree of caution in applying the approach. Our results favour combining uncertainty calibration with CVM-X in which hypothetical bias in risk attitudes is also taken account to correct for hypothetical bias in WTP.     

A Learning Design for Reducing Hypothetical Bias in the Contingent Valuation Method

Over the last few years a great deal of research has focussed on hypothetical bias in value estimates obtained with the contingent valuation (CV) method and on means for ameliorating if not eliminating such bias. To date, efforts to eliminate hypothetical bias have relied on calibration techniques or on word-smithing of one kind or another to induce subjects to provide responses to hypothetical questions that mimic responses made by subjects facing actual payments in the valuation experiment. This paper introduces a different approach for eliminating hypothetical bias. A design for a CV survey format is presented which provides subjects with the opportunity to learn how the CV institution works. Sequential referenda are conducted where respondents gain experience in CV settings by participating in both hypothetical and real referenda. The logic of this Learning Design is a straightforward application of the trials process used in experimental economics. We demonstrate that the Learning Design is effective in eliminating hypothetical bias in surveys concerning donations to two different public goods.     

A Meta-analysis of Hypothetical Bias in Stated Preference Valuation

Individuals are widely believed to overstate their economic valuation of a good by a factor of two or three. This paper reports the results of a meta-analysis of hypothetical bias in 28 stated preference valuation studies that report monetary willingness-to-pay and used the same mechanism for eliciting both hypothetical and actual values. The papers generated 83 observations with a median ratio of hypothetical to actual value of only 1.35, and the distribution has severe positive skewness. We find that a choice-based elicitation mechanism is important in reducing bias. We provide some evidence that the use of student subjects may be a source of bias, but since this variable is highly correlated with group experimental settings, firm conclusions cannot be drawn. There is some weak evidence that bias increases when public goods are being valued, and that some calibration methods may be effective at reducing bias. However, results are quite sensitive to model specification, which will remain a problem until a comprehensive theory of hypothetical bias is developed.JEL classifications: C9, H41, Q26, Q28     

Willingness to pay for a Green Energy program: A comparison of ex-ante and ex-post hypothetical bias mitigation approaches

The most persistently troubling empirical result in the contingent valuation method literature is the tendency for hypothetical willingness to pay to overestimate real willingness to pay. Two approaches, ex-ante and ex-post, have been developed to mitigate or eliminate the overstatement of hypothetical willingness to pay. The ex-ante approach addresses hypothetical bias in the survey design stage while the ex-post approach addresses hypothetical bias with follow-up questions to the hypothetical willingness to pay question. We find that willingness to pay estimates are similar when either the ex-ante or ex-post approach are employed. Our results suggest that the approaches should be considered as complements and not substitutes. Employing both approaches to mitigate hypothetical bias we estimate that the annual benefits of the regional amenities associated with a Green Energy program in North Carolina are $186 million.     

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.     

The Endowment Effect and Expected Utility

The endowment effect, which is well documented in the contingent valuation literature, alters people's preferences according to a reference point established in an elicitation question. In particular, the utility that people place on a bundle is both a positive function of the quantities of the goods comprising the bundle, and a negative function of any loss (real or hypothetical) that the elicitation question asks them to incur. Biases such as this have lead some to reject the contingent valuation method as a means of quantifying costs and benefits in favour of other methods of preference elicitation such as standard gambles. But, most preference elicitation methods used by economists require people to express their preferences for one good in terms of their willingness to forego some of another good. Consequently, it is reasonable to expect that, and prudent to check whether, an endowment effect is also evident in other methods of preference elicitation such as von Neumann-Morgenstern's standard gambles. Internal inconsistencies in the standard gamble method from the experimental economics literature and from a study into the value of non-fatal road injuries are shown to be evidence that an endowment effect is also at work in standard gambles.     

Moving towards an Improved Microsimulation Model of the Australian Pharmaceutical Benefits Scheme

Finding ways of curbing government expenditure on the Pharmaceutical Benefits Scheme (PBS) while maintaining social equity and access to ‘essential’ medicines is at the centre of ongoing public debate. This article describes a microsimulation model of the PBS that simulates current and future use and costs of PBS medicines under existing and different PBS policy settings, and estimates the distributional effects of policy changes. The article outlines future developments that will extend the current model to include health outcomes. Adding health outcomes will enable the debate on PBS sustainability to be advanced beyond the prevailing cost‐containment mentality to consider not only the costs of pharmaceutical use but also the benefits that result from the use of these medicines.     

Induced-Value Tests of Contingent Valuation Elicitation Mechanisms

Using an induced-value experimental design that varies whether values for a “good” are certain or uncertain and whether payment is real or hypothetical, this study investigates issues of demand revelation, hypothetical bias, and value uncertainty for four elicitation mechanisms used in contingent valuation surveys: dichotomous choice, dichotomous choice with follow-up certainty question, payment card, and multiple-bounded discrete choice. For all elicitation mechanisms, we find no evidence of hypothetical bias: voting decisions do not vary systematically when payment is hypothetical versus when it is real. Under all design conditions we find the fewest deviations between stated and induced values and the strongest evidence of demand revelation with dichotomous choice. Stated uncertainty in dichotomous choice follow-up and multiple-bounded discrete choice questions does correlate with uncertain induced values, but the signal is noisy. We discuss the implications of our findings for the design of contingent valuation surveys.     

A Comparison of Induced Value and Home-Grown Value Experiments to Test for Hypothetical Bias in Contingent Valuation

This study tests the hypothesis that hypothetical bias may not be related to value elicitation; rather it may be a value formation problem. When participants are asked to indicate their willingness to pay for an induced value good, we find no evidence of hypothetical bias for three different commodity types (public good, private good, and publicly provided private good). However, when these same subjects are asked to value homegrown goods with no pre-assigned induced value using the same elicitation mechanism, hypothetical values are roughly double actual payments in all three cases. These results support the hypothesis that the process of forming values in a homegrown setting may be a key contributor to hypothetical bias.     

A penny for your thoughts: Inducing truth-telling in stated preference elicitation

Contingent valuation often induces hypothetical bias. In a laboratory experiment, we test three calibration mechanisms: cheap-talk, consequentialism, and a new mechanism, the Bayesian truth serum (“BTS”). We apply the BTS in a “faith-based” format: subjects are informed about the purpose and potential efficacy of the BTS, but not its theoretical foundations. We find that real and hypothetical responses differ significantly; real and consequentialist responses are statistically indistinguishable; cheap-talk and the BTS eliminate bias inconsistently; subject characteristics interact significantly with treatment.     

Eliciting Willingness to Pay without Bias using Follow-up Certainty Statements: Comparisons between Probably/Definitely and a 10-point Certainty Scale

Correction for hypothetical bias using follow up certainty questions often takes one of two forms: (1) two options, “definitely sure” and “probably sure”, or (2) a 10-point scale with 10 very certain. While both have been successful in eliminating hypothetical bias from estimates of WTP by calibrating based on the certainty of yes responses, little is known about the relationship between the two. The purpose of this paper is to compare the two using data from three field experiments in a private good, dichotomous choice format. We compare four types of yes responses that differ in the criterion used to determine if there is sufficient certainty for a hypothetical yes response to be considered a true yes response. We make several comparisons, but focus on determining which values on the 10-point scale give the same estimates of WTP as “definitely sure” hypothetical yeses and real yeses (actual purchases). Values that produce equivalence are near 10 on the certainty scale.     

Resolving questions about bias in real and hypothetical referenda

Despite 10 years of research on behavior in hypothetical referenda, conflict remains in the literature on whether or not the mechanism generates biased responses compared to real referenda, and the nature and source of any such bias. Almost all previous inquiry in respect of this issue has concentrated on bias at the aggregate level. This paper reports a series of three experiments which focuses on bias at the individual level and how this can translate to bias at the aggregate level. The authors argue that only an individual approach to hypothetical bias is consistent with the concept of incentive compatibility. The results of these experiments reflect these previous conflicting findings but go on to show that individual hypothetical bias is a robust result driven by the differing influence of pure self-interest and other- regarding preferences in real and hypothetical situations, rather than by a single behavioral theory such as free riding. In a hypothetical situation these preferences cause yea-saying and non-demand revealing voting. This suggests that investigation of individual respondents in other hypothetical one-shot binary choices may also provide us with insights into aggregate behavior in these situations. Alphabetical list of authors no seniority of authorship attributed.     

Contingent valuation: A new perspective

After several decades of academic research on the contingent valuation (CV) method a consistent behavioral explanation of ‘hypothetical bias’ is still lacking. Based on evidence from economics, economic psychology and the political sciences, I propose an explanation that is based on two simple working hypotheses about respondent behavior in contingent valuation surveys. The first hypothesis is that survey respondents are unable to form consistent preferences about unfamiliar goods unless the choice context offers reliable, informative cues which can be rationally exploited in simplified heuristics. The second hypothesis is that the probability and impact of strategic responses in dichotomous-choice questions about public goods depends on the extent to which the presented hypothetical costs differ from the actual costs. The literature on hypothetical bias is revisited in the light of these behavioral hypotheses. I find that the hypotheses are generally supported by the empirical data. Moreover, the hypotheses are able to explain several important empirical phenomena that previous research has not been able to explain. In particular, they solve the puzzle that pre-election polls, but not CV surveys, are able to predict actual referendum outcomes, and they explain why income effects on willingness to pay are lower in CV responses than in actual votes. If confirmed by further studies, the hypotheses will have important implications for future research and practice. First, the hypothetical costs presented in the dichotomous-choice question should to be close enough to the actual costs to be credible to all respondents. This can be achieved by specifying the costs as a percentage (rather than absolute) change in taxes. Second, the respondents should be given the option to answer based on information about the positions of large parties and interest groups with known political orientation rather than based on the raw policy information. Theory and evidence suggest that this new survey paradigm largely eliminates the fundamental problems of the conventional stated preference methods.     

Does context matter more for hypothetical than for actual contributions? Evidence from a natural field experiment

We investigated the importance of the social context for people’s voluntary contributions to a national park in Costa Rica, using a natural field experiment. Some subjects make actual contributions while others state their hypothetical contribution. Both the degree of anonymity and information provided about the contributions of others influence subject contributions in the hypothesized direction. We found a substantial hypothetical bias with regard to the amount contributed. However, the influence of the social contexts is about the same when the subjects make actual monetary contributions as when they state their hypothetical contributions. Our results have important implications for validity testing of stated preference methods: a comparison between hypothetical and actual behavior should be done for a given social context.      

Socially optimal procurement with tight budgets and rationing

We investigate the behaviour of a social planner that secures the supply of a good, e.g. an environmental benefit, through contracting with private agents. While the social planner seeks to maximise net social benefits, she is also controlled with a fixed budget. Private agents are profit maximising and hold private information concerning their variable costs of production. They also have known fixed costs of contracting. We find that budget constraints and fixed costs change the optimal contract design in more than one way: the social planner minimises costs, rations high-cost contracts to reduce fixed costs and information rents, and distorts contracts for all agent types, including low-cost agents. We find that rationing improves social welfare. Also, even though social costs – including tax distortion – are explicitly taken into consideration, they do not affect the design of optimal contracts when budgets are tight. In those cases the budget constraint dominates the solution.     

Design of Stated Preference Surveys: Is There More to Learn from Behavioral Economics?

We discuss the design of stated preference (SP) surveys in light of findings in behavioral economics such as context dependence of preferences, learning, and differences between revealed and normative preferences. More specifically, we discuss four different areas: (1) revealed and normative preferences, (2) learning and constructed preferences, (3) context dependence, and (4) hypothetical bias. We argue that SP methods would benefit from adapting to some of the findings in behavioral economics, but also that behavioral economics may gain insights from studying SP methods.     

The impact of downward social information on contribution decisions

In this paper we study the effect of downward social information in contribution decisions to fund public goods. We describe the results of a field experiment run in conjunction with the fundraising campaigns of a public radio station. Renewing members are presented with social information (information about another donor’s contribution) which is either above or below their previous (last year’s) contribution. We find that respondents change their contribution in the direction of the social information; increasing their contribution when the social information is above their previous contribution, and decreasing their contribution when the social information is below. We hypothesize about the psychological motivations that may cause the results and test these hypotheses by comparing the relative size of the upward and downward shifts. These results improve our understanding of cooperation in public good provision and suggest differential costs and benefits to fundraisers in providing social information.      

Staged financing: a trade-off theory of holdup and option value

This paper investigates financial contract design in venture capital investments and shows that staged financing is the implementation of optimal contracts. In designing contracts, venture capitalists consider the value of real options and the costs of holdup. This consideration boils down to contract rigidity and flexibility: rigid contracts mitigate the holdup problem of entrepreneurs, but have little option values, whereas flexible contracts create real options for venture capitalists in corporate decision-making, but yield weak bargaining power when ventures appear promising. In optimal contracts, venture capitalists choose flexibility by separating capital into stages and then strategically allocating control rights at each stage. This strategy creates option value in corporate governance, and can protect sunk investments in distress while capturing the potential benefits of good outcomes.