Estimating a Preference-based Index From The CORE-OM For Common Mental Health Problems (CORE-6D)
This project aims to produce a preference-based measure for common mental health problems derived from the CORE-OM. The project develops methodology that can be used to derive a preference-based measure where some of the dimensions are highly correlated and are therefore not independent.
The CORE-OM is a 34-item measure monitoring clinical outcomes of people with common mental health problems. CORE-OM is characterised by high correlation across its domains. The project used Rasch analysis to reduce the number of items and response levels in order to produce a set of unidimensionally-behaving items. Rasch analysis was subsequently used to generate a credible set of health states corresponding to different levels of symptom severity using the Rasch item threshold map.
The proposed methodology resulted in the development of CORE-6D, a 2-dimensional health state description system consisting of a unidimensionally-behaving 5-item emotional component and a physical symptom item. Inspection of the Rasch item threshold map of the emotional component helped identify a set of 11 plausible health states, which, combined with the physical symptom item levels, were used to value the classification system.
A valuation study was conducted using time trade-off on a random sample of the UK general population. Interviews were successfully conducted on a sample of 225 respondents. The data is currently being analysed.
This research is being undertaken as part of a PhD by Ifigeneia Mavranezouli at the University of Sheffield.
Mavranezouli I, Brazier JE, Young TA, Barkham M. Using Rasch analysis to form plausible health states amenable to valuation: the development of the CORE-6D from a measure of common mental health problems (CORE-OM). Quality of Life Research (in press)