Comparing contingent valuation and contingent ranking: a case study considering the benefits of urban river water quality improvements.

This paper contrasts applications of both the contingent valuation (CV) and contingent ranking (CR) methods as applied to a common issue, the valuation of improvements to the water quality of an urban river (the River Tame, running through the city of Birmingham, UK). Building upon earlier experimental work, the CV design used ensures that respondents are fully aware of all impending valuation tasks prior to undertaking any one of those tasks. Such an approach is directly comparable to the CR design for which full awareness of all options is a pre-requisite. Findings indicate that the CV responses exhibit strong internal consistency with expected relationships observed between values and theoretically expected parameters. External comparisons show that CR valuations are substantially larger than those elicited through CV (with protest votes excluded), and that the response rate for the CR survey is significantly higher than that for the CV survey.