A contingent valuation study is conducted to estimate willingness to pay (WTP) for reducing skin cancer risks. A split sample design contrasts dichotomous choice (DC) with open-ended (OE) methods for eliciting WTP. A novel scope test varies the remit of risk reductions from just the individual respondent to their entire household allowing us to examine both the statistical significance and scale of scope sensitivity. While OE responses fail such tests, DC responses pass both forms of testing. We conclude that conformity of the size of scope effects with prior expectations should form a focus for future validity testing.