A (latent) class of their own
van Nooten, F. E., Houghton, K., van Exel, J., van Agthoven, M., Brouwer, W. B. F., & Stull, D. E. (2017). A (latent) class of their own: Response patterns in trading off quantity and quality of life in time trade-off exercises. Value in Health, 20(10), 1403-1410. DOI: 10.1016/j.jval.2017.06.008
BACKGROUND: Conflicting results regarding associations of time trade-off (TTO) valuations with respondent characteristics have been reported, mostly on the basis of regression analyses. Alternative approaches, such as the latent class analysis (LCA), may add to the further understanding of variations in TTO responses.
OBJECTIVES: To identify whether subgroups of respondents can be identified on the basis of their responses to TTO exercises and to investigate which respondent characteristics are associated with membership of the identified subgroups.
METHODS: Members of the Dutch general public, aged 18 to 65 years, completed a Web-based questionnaire concerning sociodemographic characteristics, three TTO exercises valuing health states described using the domains of the EuroQol five-dimensional questionnaire, and preference for quality versus quantity of life. LCA was used to identify patterns in the responses. Predictive variables were included in the final LCA model to identify the particular respondent characteristics that predict subgroup membership.
RESULTS: The sample consisted of 1067 respondents. Four latent classes were identified in the responses to TTO exercises. Two were high traders, focusing on quality of life and trading off a relatively high number of years. The other two were low traders, focusing on length of life. Predictive analyses revealed significant differences between subgroups in terms of age, sex, subjective life expectancy, and preference for quantity over quality of life.
CONCLUSIONS: We showed that distinct classes of respondents can be discerned in TTO responses from the general public, distinguishing subgroups of low and high traders. More research in this area should confirm our findings and investigate their implications for health state valuation exercises.