Influence of elicitation procedure and phrasing on health state valuations in experience-based time trade-off tasks among diabetes patients in China

Purpose Open-ended and iteration-based time trade-off (TTO) tasks can both be used for valuation of health states. It has so far not been examined how the elicitation procedure affects the valuation of experience-based health states. The purpose of this study is to investigate the influence of elicitation procedure on experience-based health state values elicited by the TTO method. Methods 156 Chinese adults with type 2 diabetes participated in face-to-face interviews with an open-ended or an iteration-based TTO task. The association between the type of TTO task and the valuation of health states was investigated through multiple linear regression analyses. A modified open-ended TTO task was also developed (n = 33) to test whether different phrasings of open-ended TTO tasks influence TTO values. Results Higher TTO values were observed in the original open-ended TTO task compared to the iteration-based task, which indicates that the elicitation procedure influences the valuation of health states. When the modified open-ended task was introduced, the difference between the two elicitation procedures was no longer statistically significant, suggesting that the phrasing and/or visual presentation of the TTO task may influence the valuation of health states. Conclusions The choice of elicitation procedure as well as the description of experience-based TTO tasks may influence the valuation of health states. Further research is warranted, also in other cultural contexts, to further explore these findings.

Manipulating the 5 Dimensions of the EuroQol Instrument: The Effects on Self-Reporting Actual Health and Valuing Hypothetical Health States

Background. The EQ-5D instrument has 5 dimensions. This article reports on the effects of manipulating a) the order in which the 5 dimensions are presented (appearing first v. last), b) splitting of the composite dimensions (“pain or discomfort” and “anxiety or depression”), and c) removing or “bolting off” 1 of the 5 EQ-5D dimensions at a time. The effects were examined in 2 contexts: 1) self-reporting health and 2) health state valuations. Methods. Three different types of discrete choice experiments (DCE) including a duration attribute were designed. An online survey with 12 subtypes, each with 10 DCE tasks, was designed and completed by 2494 members of the UK general public. Results. Of the 3 manipulations in the self-reporting context, only b) splitting anxiety or depression had a significant effect. In the health state valuation context, b) splitting level 5 pain or discomfort (relative to pain) and splitting level 5 anxiety or depression (relative to anxiety) had significant effects as did c) bolting off dimensions. Conclusions. We find that the values given to certain health dimensions are sensitive to the way in which it is described and the other health dimensions presented. Of particular interest is the effect of splitting composite dimensions: a given EQ-5D(-5L) profile may mean different things depending on whether the profile is used to self-report one’s health or to value hypothetical states, so that the health state values of EQ-5D(-5L) in population tariffs may not correspond to the states that patients self-report themselves in.