title: Mapping between Visual Analogue Scale and Standard Gamble data; results from the UK Health Utilities Index 2 valuation survey.
abstract: We examine the relationship between Visual Analogue Scale (VAS) and Standard Gamble (SG) assumed in the development of the multiplicative multi-attribute utility functions (M-MAUFs) for the Health Utilities Index (HUI) Mark 2 and Mark 3, using data from a UK valuation study of the HUI2. A range of functional forms are considered, and are compared on the basis of their explanatory power and predictive ability.A restricted cubic function fits the data better than a power curve with a mean absolute error (MAE) of 0.025 and root mean square error (RMSE) of 0.029 compared to a MAE of 0.135 and RMSE of 0.135 for the power curve. The use of a cubic mapping function instead of a power function leads to different predicted health state values. We question the reliance on the assumption of a power curve relationship between VAS and SG data, in the Health Utilities Index valuation framework. Our results demonstrate that further work is required to examine the appropriateness of the published M-MAUFs for the Health Utilities Indices.
authors.affiliation: Health Economics and Decision Science, ScHARR, University of Sheffield, UK. K.Stevens@Sheffield.ac.uk
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Stevens
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: McCabe
authors.forename: John E
authors.initials: JE
authors.lastname: Brazier
mesh_terms: D003625:Data Collection; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D010147:Pain Measurement; D012680:Sensitivity and Specificity; D006113:United Kingdom