Information and effort in contingent valuation surveys: application to global climate change using national internet samples

This contingent valuation study investigates the issues of information access and respondent effort, and is based on a series of national Internet samples. The focus is on a split-sample treatment, Basic Information (BI) versus Enhanced Information (EI). In the latter, significantly expanded information is provided about global climate change and the Kyoto Protocol. Using a referendum format, we compare the treatment effect (BI versus EI) on willingness to pay (WTP). We develop measures of respondent effort in accessing optional information, through the technology of Web-based surveys, and jointly model effort and WTP using a simultaneous estimation approach. Results support the use of the joint modeling approach for objective measures of respondent effort and WTP. Respondent effort is shown to be positively and significantly related to WTP. However, use of the optional menu is rather modest (counts of pages and time spent), and is highly variable (both across pages and respondents).