Quality of life: What is it and can it be measured?

The characteristics of quality of life scales should be considered in order to understand the extent to which they differ from disease-specific instruments, such as the Arthritis Impact Measurement Scale, or general health scales, such as the Sickness Impact Profile. A good quality of life scale assesses dimensions of everyday life that are missed by more narrowly designed, health-specific scales. To be valid, however, quality of life scales should: contain a broad range of domains relevant to the condition or treatment under study; assess recent time periods; be sensitive enough to monitor expected changes; contain a sufficient range to include patient conditions; contain both positive and negative items; and contain selective, subjective evaluations. It is important also to evaluate the strengths and weaknesses of popular quality of life measures, such as the Quality of Life Index, the Quality of Well-Being Scale, EuroQol and SF-36. (C) 1998 Churchill Livingstone.