Conducting a Time Trade-off Study Alongside a Clinical Trial: A Case Study and Recommendations


Time trade-off (TTO) is an established method in health economics to elicit and value individuals’ preferences for different health states. These preferences are expressed in the form of health-state utilities that are typically used to measure health-related quality of life and calculate quality-adjusted life-years in an economic evaluation. The TTO approach to directly elicit health-state utilities is particularly valuable when generic instruments (e.g. EQ-5D) may not fully capture changes in utility in a clinical trial. However, there is limited guidance on how a TTO study should be conducted alongside a clinical trial despite it being a valuable tool. We present an account of the design and development of a TTO study within a clinical trial as a case study. We describe the development of materials needed for the TTO interviews, the piloting of the TTO materials and interview process, and recommendations for future TTO studies. This paper provides a practical guide and reference for future applications of the TTO method alongside a clinical trial.

Key Points for Decision-Makers
– A time trade-off study is a feasible method to elicit patient preferences and value short-term changes in quality of life alongside a clinical trial.
– Extensive piloting and revisions are required when developing the time trade-off materials to ensure they are fit for purpose. The involvement of clinicians and patients during this process is essential.
– The complex nature of time trade-off interviews is likely to require face-to-face interviews, and together with an extensive development process, it is important that sufficient time and funding is allocated for the process.
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