Quality of life (QOL) assessment has rapidly become an integral variable of outcome in clinical research; over 1,000 new articles each year are indexed under "quality of life" (1). Despite the proliferation of instruments and the burgeoning theoretical literature devoted to QOL evaluation, no unified approach has been derived for its measurement, and little agreement has been attained on what it means (2). Lack of clarity regarding the definition of QOL has led to several related concepts, namely functional status, life-satisfaction, well-being, and health status, being used interchangeably with QOL (3), further contributing to ambiguity. Compared to the general population, patients with end-stage renal disease (ESRD) experience a poorer QOL (4). Questionnaire-based QOL measurement in ESRD has demonstrated that QOL is best in renal transplantation and worst in unit-based haemodialysis. The main determinants of difference are the physical function domains. QOL in ESRD has traditionally been measured by a number of disease-specific, domain-specific and generic instruments, all exhibiting a fixed design. However, the fixed nature of the aforementioned instruments, is problematic in that what is measured is predetermined and hence may not represent the free choice of the individual whose QOL is assessed (5). Questionnaire-based instruments may not reflect individual priorities.