The use of rasch analysis in reducing a large condition-specific instrument for preference valuation: the case of moving from AQLQ to AQL-5D.
The majority of health-related quality-of-life instruments are not preference-based measures and so cannot be used within cost utility analysis. The Asthma Quality of Life Questionnaire (AQLQ) is one such instrument. The aim of this study was to develop a health state classification that was amenable to valuation from the AQLQ, this being the 1st stage in developing a condition-specific preference-based measure for asthma patients. Rasch models were applied to samples of responders to the AQLQ with the aim of selecting a number of items for a preference-based utility measure (AQL-5D). Selection of items for the evaluation survey was supported with classical psychometric criteria for item selection (feasibility, internal consistency, floor and ceiling effects, and responsiveness). Rasch analysis proved to be a useful tool in assisting in the initial process of selecting items from an existing health-related quality-of-life instrument in the construction of the AQL-5D. The method is recommended for use alongside classical psychometric testing to aid in the development of preference-based measures.
Young
Tracey A
TA
School of Health and Related Research (TAY, YY, JEB, AT) The University of Sheffield, Sheffield, United Kingdom.|Yorkshire and Humber Research Design Service (TAY) The University of Sheffield, Sheffield, United Kingdom.
Yang
Yaling
Y
School of Health and Related Research (TAY, YY, JEB, AT) The University of Sheffield, Sheffield, United Kingdom.
Brazier
John E
JE
School of Health and Related Research (TAY, YY, JEB, AT) The University of Sheffield, Sheffield, United Kingdom.
Tsuchiya
Aki
A
School of Health and Related Research (TAY, YY, JEB, AT) The University of Sheffield, Sheffield, United Kingdom.|Department of Economics (AT) The University of Sheffield, Sheffield, United Kingdom.
D000223:Adaptation, Psychological; D001249:Asthma / Q000473:pathology / Q000523:psychology*; D016009:Chi-Square Distribution; D005240:Feasibility Studies; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D008960:Models, Psychological; D015233:Models, Statistical; D017060:Patient Satisfaction; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D019057:Quality-Adjusted Life Years; D011795:Surveys and Questionnaires