During the 26 years since EQ-5D was first developed, a substantial amount of research has been carried out worldwide using the instrument. Among these studies were surveys conducted in various countries that measured the health-related quality of life of the general population. These studies have been informative in providing new data on population health characteristics, complementing the tradi- tionally collected morbidity and mortality data. The EuroQol Group is frequently asked to provide EQ-5D population reference data (sometimes called population norm data or simply population norms) for a specific country or international region. Such data can be used to compare profiles for patients with specific conditions with data for the average person in the general population in a similar age and/or gender group. Also the burden of disease in question can be compared to the general population’s health.