Keeping up appearances: Motivations for socially desirable responding in contingent valuation interviews

The tendency to give socially desirable rather than true statements of willingness to pay (WTP) is an often reported form of bias in contingent valuation surveys. While previous research on this bias has exclusively focused on the detection of mode effects, the present study directly assesses a respondent's motivation to state WTP in a socially desirable manner. This study tests the effect of three theoretical motivations for socially desirable responding on WTP responses: A general need for social approval, a perceived social norm calling for a high contribution and perceived lack of anonymity of the interview situation. Questions for the empirical assessment of these factors are developed.

Results of a valuation study in Southwest China show differing and independent impacts of these factors. While there is no effect of perceived anonymity, need for social approval biases WTP responses upwards but does not influence the general decision to state a positive WTP. It also turns out that rather the fear of losing social status than the striving for higher social approval is the main driver of this bias. Respondents perceiving a social norm for high WTP are more likely to state a positive WTP, but the specific amount is not affected.