The Swedish Health-Related Quality of Life Survey (SWED-QUAL).

We present a Swedish Health-Related Quality of Life Survey (SWED-QUAL) that was adapted from measures used in the Medical Outcome Study (MOS). The development of these measures spans more than 20 years and their reliability and validity have been extensively tested. The SWED-QUAL consists of 61 items that form 11 multi-item scales tapping aspects of physical, mental, social and general health. The instrument was mailed in 1991 to a random stratified sample of 2,366 individuals from the Swedish general population aged 18-84 years and to a stratified random sample of 2,349 individuals who had been seriously injured in a traffic accident. The response rates were 61% and 59%, respectively. Telephone follow-up of non-responders indicate that most of those tended to have a better health-related quality of life than responders. The SWED-QUAL satisfied all of the psychometric criteria that were evaluated. Multitrait scaling provided strong support for item discrimination. Cronbach's alpha exceeded 0.78 for all scales. Scores tended to be lower among older than younger people, and among females compared to males. The good response rate indicates that the content of the SWED-QUAL is considered relevant by people at large, that the results from the general population sample could be used for comparisons with other samples and the instrument used for further studies of the effectiveness of a broad spectrum of medical interventions.