The sampling frame was based on (1) the sample size and sample diversity necessary to develop a general health-related quality of life measure, and (2) a standardized protocol across 15 culturally diverse centers.

determined by the practical limitations of following.

A pilot WHOQOL was administered to at least 300 respondents in each of the 15 field centers participating in this his 4,444 phase of the project.

Field centers were directed to administer the pilot WHOQOL to adults, resulting in culturally defined 'adults'.

Sampling allocation was set by age (50% > 45, 50%).