Using a discrete choice experiment to value the QLU-C10D: feasibility and sensitivity to presentation format.
OBJECTIVE
To assess the feasibility of using a discrete choice experiment (DCE) to value health states within the QLU-C10D, a utility instrument derived from the QLQ-C30, and to assess clarity, difficulty, and respondent preference between two presentation formats.


METHODS
We ran a DCE valuation task in an online panel (N = 430). Respondents answered 16 choice pairs; in half of these, differences between dimensions were highlighted, and in the remainder, common dimensions were described in text and differing attributes were tabulated. To simplify the cognitive task, only four of the QLU-C10D's ten dimensions differed per choice set. We assessed difficulty and clarity of the valuation task with Likert-type scales, and respondents were asked which format they preferred. We analysed the DCE data by format with a conditional logit model and used Chi-squared tests to compare other responses by format. Semi-structured telephone interviews (N = 8) explored respondents' cognitive approaches to the valuation task.


RESULTS
Four hundred and forty-nine individuals were recruited, 430 completed at least one choice set, and 422/449 (94 %) completed all 16 choice sets. Interviews revealed that respondents found ten domains difficult but manageable, many adopting simplifying heuristics. Results for clarity and difficulty were identical between formats, but the "highlight" format was preferred by 68 % of respondents. Conditional logit parameter estimates were monotonic within domains, suggesting respondents were able to complete the DCE sensibly, yielding valid results.


CONCLUSIONS
A DCE valuation task in which only four of the QLU-C10D's ten dimensions differed in any choice set is feasible for deriving utility weights for the QLU-C10D.
School of Public Health, Curtin University, Perth, Australia. Richard.norman@curtin.edu.au.|Centre for Health Economics Research and Evaluation (CHERE), University of Technology Sydney (UTS), Sydney, Australia. Richard.norman@curtin.edu.au.
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R
Norman
Centre for Health Economics Research and Evaluation (CHERE), University of Technology Sydney (UTS), Sydney, Australia.
R
R
Viney
The Netherlands Cancer Institute, Amsterdam, The Netherlands.
N K
NK
Aaronson
School of Health and Related Research, University of Sheffield, Sheffield, South Yorkshire, UK.
J E
JE
Brazier
Department of Medical Social Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
D
D
Cella
Psycho-Oncology Cooperative Research Group (PoCoG), University of Sydney, Sydney, Australia.
D S J
DS
Costa
Institute of Applied Health Sciences, University of Aberdeen, Aberdeen, UK.|Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
P M
PM
Fayers
Innsbruck Medical University, Innsbruck, Austria.
G
G
Kemmler
Faculty of Health Sciences, Simon Fraser University, Vancouver, Canada.|Canadian Centre for Applied Research in Cancer Control (ARCC), Vancouver, Canada.|British Columbia Cancer Agency, Vancouver, Canada.
S
S
Peacock
Department of Pharmacy Systems, Outcomes and Policy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA.
A S
AS
Pickard
School of Health and Related Research, University of Sheffield, Sheffield, South Yorkshire, UK.
D
D
Rowen
School of Mathematical and Physical Sciences, University of Technology Sydney, Sydney, Australia.
D J
DJ
Street
Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.|St James's Hospital, Leeds, UK.
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G
Velikova
School of Health and Related Research, University of Sheffield, Sheffield, South Yorkshire, UK.
T A
TA
Young
Psycho-Oncology Cooperative Research Group (PoCoG), University of Sydney, Sydney, Australia.|Central Clinical School, Sydney Medical School, University of Sydney, Sydney, Australia.
M T
MT
King
D002755:Choice Behavior; D005260:Female; D006304:Health Status; D006801:Humans; D016015:Logistic Models; D008297:Male; D009369:Neoplasms / Q000523:psychology*; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life / Q000523:psychology*; D011795:Surveys and Questionnaires; D013689:Telephone
Cancer; Discrete choice experiment; QLQ-C30; Quality of life; Utility