School of Dental Sciences, Newcastle University, Newcastle upon Tyne, UK.
Yunus Centre for Social Business and Health, Glasgow Caledonian University, Glasgow, UK.
Med Decis Making. 2021 May;41(4):465-474. doi: 10.1177/0272989X21996329. Epub 2021 Mar 18.
Willingness to pay (WTP) is used to generate information about value. However, when comparing 2 or more services using standard WTP techniques, the amounts elicited from participants for the services are often similar, even when individuals state a clear preference for one service over another. An incremental approach has been suggested, in which individuals are asked to first rank interventions and provide a WTP value for their lowest-ranked intervention followed by then asking how much more they are willing to pay for their next preferred choice and so on. To date, evaluation of this approach has disregarded protest responses, which may give information on consistency between stated and implicit rankings.
A representative sample of the English population ( = 790) were asked to value 5 dental services adopting a societal perspective, using a payment vehicle of additional household taxation per year. The sample was randomized to either the standard or the incremental approach. Performance for both methods is assessed on discrimination between values for interventions and consistency between implicit and stated ranks. The data analysis is the first to retain protest responses when considering consistency between ranks.
The results indicate that neither approach provides values that discriminate between interventions. Retaining protest responses reveals inconsistencies between the stated and implicit ranks are present in both approaches but much reduced in the incremental approach.
The incremental approach does not improve discrimination between values, yet there is less inconsistency between ranks. The protest responses indicate that objections to giving values to the dental interventions are dependent on a multitude of factors beyond the elicitation process.
意愿支付（Willingness to pay，WTP）用于获取有关价值的信息。然而，当使用标准 WTP 技术比较两种或更多服务时，即使个体明确表示更喜欢一种服务而不是另一种服务，从参与者那里得出的用于这些服务的金额通常也相似。已经提出了一种增量方法，其中要求个人首先对干预措施进行排名，并为其排名最低的干预措施提供 WTP 值，然后再询问他们为下一个首选选择愿意多支付多少，依此类推。迄今为止，对这种方法的评估忽略了抗议反应，这些反应可能会提供有关明确和隐含排名之间一致性的信息。
采用家庭每年额外纳税额作为支付手段，从英国代表性人群中抽取了 790 名代表，要求他们对 5 种牙科服务进行估值。将样本随机分配到标准方法或增量方法。这两种方法的性能均基于干预措施价值的区分度和隐含与明确排名之间的一致性进行评估。这是第一个在考虑排名一致性时保留抗议反应的数据分析。
结果表明，这两种方法都无法提供可区分干预措施的价值。保留抗议反应表明，在两种方法中都存在明确和隐含排名之间的不一致，但在增量方法中则大大减少。
增量方法不能提高价值区分度，但排名之间的不一致性较小。抗议反应表明，对给牙科干预措施赋值的反对意见取决于除启发式过程之外的许多因素。
