Erasmus Centre for Health Economics Rotterdam, Erasmus School of Health Policy & Management, Erasmus University Rotterdam, Rotterdam, Netherlands.
Institute for Medical Technology Assessment, Erasmus University Rotterdam, Rotterdam, Netherlands.
Health Econ. 2022 Aug;31(8):1633-1648. doi: 10.1002/hec.4529. Epub 2022 Apr 26.
Time trade-off utilities have been suggested to be biased upwards. This bias is a result of the method being applied assuming linear utility of life duration, which is violated when individuals discount future life years or are loss averse for health. Applying a "corrective approach", that is, measuring individuals' discount function and loss aversion and correcting time trade-off utilities for these individual characteristics, may reduce this bias in utilities. Earlier work has developed this approach for time trade-off in a student sample. In this study, the corrective approach was extended to composite time trade-off (cTTO) methodology, which enabled correcting utilities for health states worse than dead. In digital interviews a sample of 150 members of the general public completed cTTO tasks for six health states, and afterward they completed measurements of loss aversion and discounting. cTTO utilities were corrected using these measurements under multiple specifications. Respondents were also asked to reflect on and adjust their cTTO utilities directly. Our results show considerable loss aversion and both positive and negative discounting were prevalent. As predicted, correction generally resulted in lower utilities. This was in accordance with the direction of adjustments made by respondents themselves.
时间权衡效用被认为存在向上偏差。这种偏差是由于该方法假设生命持续时间的线性效用，而当个体对未来生命年限进行贴现或对健康产生损失厌恶时，这种假设就会被违反。应用“修正方法”，即测量个体的贴现函数和损失厌恶程度，并对这些个体特征进行时间权衡效用修正，可以减少效用中的这种偏差。早期的工作已经为学生样本中的时间权衡开发了这种方法。在这项研究中，修正方法被扩展到复合时间权衡 (cTTO) 方法，该方法可以为比死亡状态更差的健康状态修正效用。在数字访谈中，一个由 150 名普通公众组成的样本完成了六个健康状态的 cTTO 任务，之后他们完成了损失厌恶和贴现的测量。根据多种规范，使用这些测量值对 cTTO 效用进行了修正。受访者还被要求直接反思和调整他们的 cTTO 效用。我们的结果显示出相当大的损失厌恶，并且普遍存在正向和负向贴现。正如预期的那样，修正通常会导致较低的效用。这与受访者自己所做的调整方向一致。
