Grutters Janneke P C, Kessels Alfons G H, Dirksen Carmen D, van Helvoort-Postulart Debby, Anteunis Lucien J C, Joore Manuela A
Department of Clinical Epidemiology and Medical Technology Assessment, University Hospital Maastricht, Maastricht, The Netherlands.
Value Health. 2008 Dec;11(7):1110-9. doi: 10.1111/j.1524-4733.2008.00340.x. Epub 2008 May 16.
Our main objective was to compare willingness to accept (WTA) and willingness to pay (WTP) in a discrete choice experiment on hearing aid provision. Additionally, income effect and endowment effect were explored as possible explanations for the disparity between WTA and WTP, and the impact of using a WTA and/or WTP format to elicit monetary valuations on the net benefit of the new organization of hearing aid provision was examined.
Choice sets were based on five attributes: performer of the initial assessment; accuracy of the initial assessment; duration of the pathway; follow-up at the ear, nose, and throat specialist; and costs. Persons with hearing complaints randomly received a WTP (costs defined as extra payment) or WTA (costs defined as discount) version of the experiment. In the versions, except for the cost attribute, all choice sets were equal.
The cost coefficient was statistically significantly higher in the WTP format. Marginal WTA was statistically significantly higher than marginal WTP for the attributes accuracy and follow-up. Disparity was higher in the high educational (as proxy for income) group. We did not find proof of an experience endowment effect. Implementing the new intervention would only be recommended when using WTP.
WTA exceeds WTP, also in a discrete choice experiment. As this affects monetary valuations, more research on when to use a payment or a discount in the cost attribute is needed before discrete choice results can be used in cost-benefit analyses.
我们的主要目标是在一项关于助听器提供的离散选择实验中比较接受意愿（WTA）和支付意愿（WTP）。此外，还探讨了收入效应和禀赋效应，作为对WTA和WTP之间差异的可能解释，并研究了使用WTA和/或WTP形式来引出货币估值对助听器提供新组织的净效益的影响。
选择集基于五个属性：初始评估的执行者；初始评估的准确性；流程持续时间；耳鼻喉专科医生的随访；以及成本。有听力问题的人被随机分配接受实验的WTP（成本定义为额外支付）或WTA（成本定义为折扣）版本。在这些版本中，除了成本属性外，所有选择集都是相同的。
WTP形式下的成本系数在统计学上显著更高。对于准确性和随访这两个属性，边际WTA在统计学上显著高于边际WTP。高教育程度（作为收入的代理指标）组的差异更大。我们没有找到经验禀赋效应的证据。只有在使用WTP时才建议实施新的干预措施。
在离散选择实验中，WTA也超过WTP。由于这会影响货币估值，在离散选择结果可用于成本效益分析之前，需要对成本属性中何时使用支付或折扣进行更多研究。
