Preference-based measures

Preference-based measures (PBM) are being increasingly used in health economic evaluations to calculate quality-adjusted life years (QALYs). Such measures usually comprise several domains (or a descriptive set) that patients can use to describe various aspects of their health (e.g. limitations in daily activities and mobility, pain and discomfort). These patient-reported values (profile scores) are then converted to an index score using a selected algorithm (sometimes country-specific). These algorithms are based on surveying the general public’s preferences for different combinations of health states, which is why these measures are referred to as “preference-based”. The index scores (sometimes called ‘utilities’) usually range between 0 and 1, where 1 is usually taken to reflect a valuation of ”perfect health” and 0 refers to a valuation of “death”. In some of these measures, values below 0 may be possible, representing health states perceived to be worse than death. Examples of PBMs include the EQ-5D, SF-6D and the Health Utilities Index. The EQ-5D is NICE’s preferred instrument for cost-utility evaluations in healthcare technology assessments.