It's not justwhatyou do, it's thewaythat you do it: the effect of different payment card formats and survey administration on willingness to pay for health gain
研究比较了面对面和电话调查两种方式，以及三种支付卡格式（从高到低、从低到高、随机排列）对健康收益支付意愿的影响，发现电话调查更快但结果无显著差异，而高到低格式产生显著更高的支付意愿值。
A general population sample of 314 Australian respondents were randomly allocated to complete a contingent valuation survey administered by face-to-face or telephone ('phone-mail-phone') interview. Although the telephone interview was quicker to complete, no significant difference was found in values obtained through either method. Within each sub-sample, respondents were also randomly allocated to the three different versions of the payment card (PC) questionnaire format: values listed from high-to-low, values listed from low-to-high and values randomly shuffled. The high-to-low version resulted in significantly higher values than the other versions. Further analyses indicate that the randomly shuffled PC version may produce the most 'valid' values.