Preliminary validation study of the Portuguese version of the satisfaction with life scale.

The 'satisfaction with life scale' (SWLS) is a concise instrument for comprehensive and self-rated assessment of subjective well-being. The objective was to evaluate the reliability (test-retest), internal structure and discriminant validity of the SWLS in Portugal. The reliability was studied in general medical patients hospitalised in a general medical ward. The SWLS was administered on two occasions and the correlation coefficients ('r') between both interviews were calculated. Its discriminant validity was studied statistically comparing the average score in a group of patients with arthritis (with presumed lower subjective well-being) and the average score in a group of students and health professionals (with presumed higher subjective well-being). A high reliability r = 0.86 was found for the total score. The discriminant validity study found a significant difference between mean total score in the samples of presumed higher (5.96) and lower (3.45) subjective well-being. A high Cronbach's alpha (0.89) was also documented. The results reported that the SWLS is reliable, has a high internal consistency, is capable of discriminating groups of presumed different subjective well-being levels, and is quite efficient and easy to use.