Test-Retest Reliability of Discrete Choice Experiment for Valuations of QLU-C10D Health States

Eva-Maria Gamper; Bernhard Holzner; Madeleine T King; Richard Norman; Rosalie Viney; Virginie Nerich; Georg Kemmler

doi:10.1016/j.jval.2017.11.012

Test-Retest Reliability of Discrete Choice Experiment for Valuations of QLU-C10D Health States

Value Health. 2018 Aug;21(8):958-966. doi: 10.1016/j.jval.2017.11.012. Epub 2018 Mar 3.

Authors

Eva-Maria Gamper¹, Bernhard Holzner², Madeleine T King³, Richard Norman⁴, Rosalie Viney⁵, Virginie Nerich⁶, Georg Kemmler²

Affiliations

¹ Department for Psychiatry and Psychotherapy, Medical University of Innsbruck, Innsbruck, Austria. Electronic address: eva-maria.gamper@i-med.ac.at.
² Department for Psychiatry and Psychotherapy, Medical University of Innsbruck, Innsbruck, Austria.
³ Psycho-Oncology Cooperative Research Group, Cancer Australia Chair in Cancer Quality of Life School of Psychology, Faculty of Science, University of Sydney, Sydney, Australia.
⁴ School of Public Health, Department of Health Policy and Management, Curtin University, Perth, Australia.
⁵ Center of Health Economics and Research Evaluation, University of Technology Sydney, Sydney, Australia.
⁶ University of Franche-Comté, Besançon, France.

PMID: 30098674
DOI: 10.1016/j.jval.2017.11.012

Abstract

Background: Recently, a newly developed cancer-specific multiattribute utility instrument based on the widely used health-related quality of life instrument, the European Organisation for Research and Treatment of Cancer QLQ-C30, was introduced: the QLU-C10D. For the elicitation of utility weights, a discrete choice experiment (DCE) was designed. Our aim was to investigate the DCE in terms of individual choice consistency and utility estimate consistency by applying a test-retest design.

Methods: We conducted the study in general population samples in Germany and France. The DCE was administered via a web-based self-complete survey using online panels. Respondents were presented 16 choice sets comprising 11 attributes with 4 levels each. Retest was conducted 4 to 6 weeks after first assessment. We used kappa and percentage agreement as measures of choice consistency and both intraclass correlations and mean utility differences as measures of utility estimate consistency.

Results: A total of 300 German respondents (31% female, mean age 48 years [SD 14]) and 305 French respondents (46% female, mean age 47 years [SD 16]) completed test and retest assessments. Individual choice consistency was moderate to high (Germany: κ = 0.605, percentage agreement = 80.2%; France: κ = 0.411, percentage agreement = 70.6%). Utility estimate consistency was high when considering intraclass correlations (all >0.79). Mean utility differences were 0.08 in the German sample and 0.05 in the French sample.

Conclusions: Results indicate that the designed DCE elicits stable health state preferences rather than guesses or mood-specific or condition-specific judgments. Nevertheless, the identified mean utility differences between test and retest need to be taken into account when determining minimal important differences for the QLU-C10D in future research.

Keywords: QLU-C10D; choice consistency; health state valuation; test-retest; utilities.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Choice Behavior*
Female
Humans
Male
Middle Aged
Neoplasms / psychology
Psychometrics / instrumentation
Psychometrics / methods
Psychometrics / standards*
Quality of Life / psychology*
Reproducibility of Results
Surveys and Questionnaires