Time trade-off (TTO) is a stated preference technique for obtaining values for health states for use in health technology assessment. NICE recommends that the value, or utility, of changes in health should be based on public preferences elicited using a choice-based method such as TTO. Accordingly, the EuroQol Group recommends the use of TTO alongside the discrete choice experiment (another choice-based technique) for valuing the EQ-5D, its flagship measure of patient-reported outcomes.

 

OHE has been involved in a number of methodological studies seeking to improve the ways in which TTO studies are designed and administered (see here for an example recently featured on this blog). One such study – just published in Value in Health – examines whether introducing two novel modifications can improve the quality of TTO data. The first modification was to separate the tasks used for valuing health states considered ‘better than dead’ from those used for valuing health states considered ‘worse than dead’. The second modification was the implementation of a ‘feedback module’ whereby study respondents could review their responses to the TTO tasks and flag any valuations that they were dissatisfied with, on reflection. The feedback module reflects the notion that it is important for respondents in stated preference studies to understand researchers’ interpretations of their choices (see here for related OHE research on this topic). 

 

The two modifications were tested using samples of the general public in the Netherlands and Hong Kong. The authors conclude that the results support the use of the feedback module to reduce logical inconsistencies in TTO data. The feedback module has subsequently been incorporated into the latest version of the EuroQol protocol for valuing the EQ-5D-5L instrument. On the other hand, separating the valuations of better than dead and worse than dead health states was found to reduce inconsistencies in the Netherlands but not in Hong Kong.

 

The paper is authored by Eliza Wong, Annie Cheung and Amy Wong of the Jockey Club School of Public Health and Primary Care Faculty of Medicine at the Chinese University of Hong Kong; Martijn Visser of the Department of Psychiatry at the Erasmus University Medical Center, Elly Stolk of the EuroQol Office, and OHE’s Koonal Shah.

 

For the next few weeks, the paper is available open access – download for free from here.

 

 

Wong, E.L., Shah, K., Cheung, A.W.L., Wong, A.Y.K., Visser, M. & Stolk, E., 2018. Evaluation of split version and feedback module on the improvement of time trade-off data. Value in Health, 21, 732-741. DOI | PubMed

 

 

Feng, Y., Hole, AR., Karimi, M., Tsuchiya, A., & van Hout, B. 2018. An exploration of the non-iterative time trade-off method to value health states. Health Economics, Early View. DOI | PubMed

 

Shah, K., Chapman, A., Devlin, N. & Barnsley, P., 2015. Do respondents completing abstract, hypothetical priority-setting exercises agree with the policy implications of their choices? Consulting Report. London: Office of Health Economics. RePEc