The truth, the whole truth, and nothing but the truth—A multiple country test of an oath script

Abstract

Hypothetical bias is one of the main issues bedeviling the field of nonmarket valuation. The general criticism is that survey responses reflect how people would like to behave, rather than how they actually behave. In our study of climate change and emissions reductions, we took advantage of the increasing bulk of evidence from psychology and economics that addresses the effects of making promises, in order to investigate the effect of an oath script in a contingent valuation survey. The survey was conducted in Sweden and China, and its results indicate that an oath script has significant effects on respondent behavior in answering willingness-to-pay (WTP) questions, some of which vary by country. In both countries, the share of zero WTP responses and extremely high WTP responses decreases when an oath script is used, which also results in lower variance. In China, the oath script also reduces the average WTP, cutting it by half in certain instances. We also found that the oath script has different impacts on various respondent groups. For example, without the oath script, Communist party members in China are more likely than others to have a positive WTP for emissions reductions, but with the oath script, there is no longer any difference between the groups.

Are Ex‐Ante Hypothetical Bias Calibration Methods Context Dependent? Evidence from Online Food Shoppers in China

“…Jacquemet et al (2017) found that making a promise can decrease or even eliminate the existence of hypothetical bias. Similarly, Carlsson et al (2013) shows that using an oath script, the share of zero WTP responses and extremely high WTP responses decreases. This approach, however, has been noted for some limitations, including the potential for participants to be bothered by the "heavy handness" of the method (de-Magistris, Gracia, and Nayga 2013).…”

“…This argument is based on evidence from social psychology that tests the effect of making a promise (Albarracín et al 2005;Durantini et al 2006;Girandola and Bernard 2007). Recent studies have investigated the effect of an oath script in environmental studies (Carlsson et al 2013;Jacquemet et al 2011Jacquemet et al , 2013Jacquemet et al , 2017 and food surveys (de-Magistris and Pascucci 2014). Jacquemet et al (2011) suggest that under oath, bidders seem to take both the budget constraint and participation constraint more seriously than with a cheap-talk script.…”

Is willingness to contribute for environmental protection in Sweden affected by social capital?

“…An individual's knowledge on environmental issues may consequently increase the probability of their WTC for environmental protection. Examples of the positive impact of education abound in the literature (Gelissen 2007;Torgler and García-Valiñas 2007;Jones et al 2009Jones et al , 2010Polyzou et al 2011;Halkos and Jones 2012;Carlsson et al 2013).…”

“…Finally, household size is expected to be negatively related to an individual's WTC for the environment. Larger households are expected to spend much of their limited budget resources on other needs than giving toward environmental protection (see Carlsson et al 2013).…”

Third party assessments in trust problems with conflict of interest: An experiment on the effects of promises

“…Subjects who took the oath were on average less likely to either overstate or understate their bids. Carlsson et al (2010) tested the oath in the field using non-market valuation surveys and found that the share of zero WTP responses and extremely high WTP responses decreases, which could be interpreted as reduced dishonesty. Shu et al (2012) find that signing a statement of honesty at the beginning instead of at the end of a self-report serves as a commitment and leads to significant reductions in misreporting.…”