Using the effect size to model change in preference values from descriptive health status.
OBJECTIVE
This pilot study describes a modelling approach to translate group-level changes in health status into changes in preference values, by using the effect size (ES) to summarize group-level improvement.


METHODS
ESs are the standardized mean difference between treatment groups in standard deviation (SD) units. Vignettes depicting varying severity in SD decrements on the SF-12 mental health summary scale, with corresponding symptom severity profiles, were valued by a convenience sample of general practitioners (n = 42) using the rating scale (RS) and time trade-off methods. Translation factors between ES differences and change in preference value were developed for five mental disorders, such that ES from published meta-analyses could be transformed into predicted changes in preference values.


RESULTS
An ES difference in health status was associated with an average 0.171-0.204 difference in preference value using the RS, and 0.104-0.158 using the time trade off.


CONCLUSIONS
This observed relationship may be particular to the specific versions of the measures employed in the present study. With further development using different raters and preference measures, this approach may expand the evidence base available for modelling preference change for economic analyses from existing data.
Centre for Health Research, School of Public Health, Queensland University of Technology, Australia. k.sanderson@qut.edu.au
Kristy
K
Sanderson
Gavin
G
Andrews
Justine
J
Corry
Helen
H
Lapsley
D000704:Analysis of Variance; D003362:Cost-Benefit Analysis; D006304:Health Status; D006801:Humans; D001523:Mental Disorders / Q000473:pathology*; D010865:Pilot Projects; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires