Background: At the beginning of the 1990s, the World Health Organization (WHO) developed a project in order to create a cross-cultural instrument of quality of life assessment: the World Health Organization Quality of Life (WHOQOL).
Purpose: This paper describes the development of the European Portuguese version of the WHOQOL-100, according to the methodology recommended by the WHO.
Method: Special attention is given to the qualitative pilot study, which led to the development of the Portuguese Facet [Political P], and to the empirical pilot study and the psychometric studies, based on the application of the Portuguese version of the instrument to a sample of 315 subjects from the general population and 289 patients. The assessment protocol also included the Beck Depression Inventory and the Brief Symptom Inventory.
Results: The Portuguese version of WHOQOL-100 showed acceptable internal consistency (alpha range 0.84-0.94) and test-retest reliability in all domains (r range 0.67-0.86). Discriminant validity was significant for all domains, except in Spirituality. Convergent validity with the Beck Depression Inventory and the Brief Symptom Inventory was satisfactory for most domains.
Conclusion: The WHOQOL showed good psychometric characteristics, suggesting that the Portuguese version of WHOQOL is valid and reliable in the assessment of quality of life in Portugal.