Validity and reliability of the Norwegian version of the Ferrans and Powers Quality of Life Index.

The purpose of this study was to examine the validity and reliability of the Norwegian version of the Ferrans and Powers Quality of Life Index in a sample of 131 men and women with newly diagnosed cancer. The Quality of Life Index was translated into Norwegian using a standardized international approach, including back-translation. The findings showed high internal consistency reliability for the global score (alpha = 0.93 (test)) as well as for the following domains: health and functioning (alpha = 0.88), socio-economic (alpha = 0.82), psychological/spiritual (alpha = 0.82) and family (alpha = 0.79). The test-retest reliability after 3-4 weeks was 0.78 for the global score. A factor analysis partially confirmed the different subscales. In conclusion, the Quality of Life Index was found to be reliable and had sufficient validity to be used for measuring quality of life in Norwegian cancer patients.