Comparison of time-tradeoff utilities and rating scale values of cancer patients and their relatives: evidence for a possible plateau relationship.
Because they are easy to administer, rating scales are often used as proxies for utility measures. The authors investigated the relationship between time-tradeoff utilities and rating scale values in two populations: 124 cancer patients asked to evaluate their current states of health and 102 relatives and close friends of cancer patients asked to evaluate health-state scenarios. None of the models tested effectively described the relationship between individual patients' rating scale values and time-tradeoff utilities for their current states of health. In contrast, both a plateau and a power-function model explained the variability in the responses of the relatives reasonably well (R2 = 0.56 and R2 = 0.58, respectively). Given that many respondents who were unwilling to trade off any time assigned rating scale values of well below 100, a plateau model may represent the best approach to adjusting rating scale values for health-state scenarios when it is not feasible to elicit time-tradeoff utilities.
O'Leary
J F
JF
Division of Cancer Epidemiology and Control, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
Fairclough
D L
DL
Jankowski
M K
MK
Weeks
J C
JC
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002755:Choice Behavior; D006304:Health Status; D006801:Humans; D008875:Middle Aged; D009369:Neoplasms / Q000401:mortality / Q000523:psychology* / Q000628:therapy; D011788:Quality of Life; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome