Abstract
Background. During preference testing, some investigators use "perfect health" as the upper anchor point of their measurement scale ("Q scale"), whereas others use "disease free" ("q scale"), which can confound the interpretation and comparison of study results. Methods. We measured current health preferences among 74 patients with cervical spondylotic myelopathy (CSM) on both the Q and q scales using the visual analogue scale (VAS), standard gamble (SG), time tradeoff (TTO), and willingness to pay (WTP). Results. There were significant differences in mean Q and q scale values for the VAS, SG, and WTP (for all, P < 0.011); there were no significant differences for mean TTO values (P = 0.592). CSM accounted for 63% to 82% of total disutility, whereas other comorbidities accounted for 28% to 37%. Conclusions. Preferences for CSM differ when measured on the Q and q scales. Caution should be used when comparing and interpreting health values measured on scales with different upper anchors.
Original language | English (US) |
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Pages (from-to) | 212-225 |
Number of pages | 14 |
Journal | Medical Decision Making |
Volume | 23 |
Issue number | 3 |
DOIs | |
State | Published - May 2003 |
Externally published | Yes |
Keywords
- Measurement
- Preferences
- Standard gamble
- Time tradeoff
- Utility
- Visual analogue scale
- Willingness to pay
ASJC Scopus subject areas
- Health Policy