The self-assessment Global Quality of Life scale: Reliability and construct validity

Objective. The aim was to establish psychometric properties of the Global Quality of Life Scale (GQL) for people with severe mental illness. Methods. GQL is a stand-alone visual analogue scale included in "The Quality Star", a minimal platform for clinical follow-up and efficiency documentation of mental health services in eight dimensions widely used in Sweden. Validating instruments included MANSA, Inventory of Problem and Solutions, Consumer Satisfaction Rating Scale, Perceived Global Distress, health screening using UKU-Side Effect Rating Scale, GAF, and Perceived Global Burden (for next of kin). Test-retest reliability of the GQL was examined between ratings at quarterly intervals during 1 year. Results. There were three main results: test-retest reliability at quarterly intervals was very satisfactory, concurrent validity with the initial item of life satisfaction scale of MANSA, "Life as a whole", was demonstrated and finally content validity was clarified by associations with a number of validating measures from several contexts in three studies. Conclusion. GQL have acceptable psychometric properties and is valid for serious mental ill persons. Its use as easy-to-use instrument for screening of perceived global quality of life was supported.