de Bekker - Grob, E., Hol, L., Donkers, B., Dam, L., Habbema, D., Leerdam, M., Kuipers, E., Bot, M. and Steyerberg, E. (2010). Labeled versus Unlabeled Discrete Choice Experiments in Health Economics: An Application to Colorectal Cancer Screening Value in Health, 13(2):315--323.

Objectives: Discrete choice experiments (DCEs) in health economics commonly present choice sets in an unlabeled form. Labeled choice sets are less abstract and may increase the validity of the results. We empirically compared the feasibility, respondents' trading behavior, and convergent validity between a labeled and an unlabeled DCE for colorectal cancer (CRC) screening programs in The Netherlands. Methods: A labeled DCE version presented CRC screening test alternatives as 'fecal occult blood test,' 'sigmoidoscopy,' and 'colonoscopy,' whereas the unlabeled DCE version presented them as 'screening test A' and 'screening test B.' Questionnaires were sent to participants and nonparticipants in CRC screening. Results: Total response rate was 276 (39%) out of 712 and 1033 (46%) out of 2267 for unlabeled and labeled DCEs, respectively (P < 0.001). The labels played a significant role in individual choices; approximately 22% of subjects had dominant preferences for screening test labels. The convergent validity was modest to low (participants in CRC screening: r = 0.54; P = 0.01; nonparticipants: r = 0.17; P = 0.45) largely because of different preferences for screening frequency. Conclusion: This study provides important insights in the feasibility and difference in results from labeled and unlabeled DCEs. The inclusion of labels appeared to play a significant role in individual choices but reduced the attention respondents give to the attributes. As a result, unlabeled DCEs may be more suitable to investigate trade-offs between attributes and for respondents who do not have familiarity with the alternative labels, whereas labeled DCEs may be more suitable to explain real-life choices such as uptake of cancer screening.