The importance of realism to experiments comparing cash and CV charitable donations: the case of the Isle of Eigg Trust

An important focus for concern about Contingent Valuation (CV) is that hypothetical payments for non-market goods are biased upwards in comparison to cash payments. Lack of realism, through its influence on incentives to mis-report payments, may explain the divergence. This paper reports on a study which attempts to overcome this problem by emulating a real fund-raising solicitation by the Isle of Eigg Trust for both real and hypothetical donations. In contrast to previous results, the mean cash donation was higher (£3.71) than the mean CV donation (£3.41). The importance of realism is highlighted by a third survey, which used a neutral CV design, implemented by a research organisation, where the mean donation was much higher (£6.21) than the cash equivalent.