Standardised health-related quality of life questionnaires play an increasi
ng role as measures of outcome in the evaluation of health care interventio
ns. However, problems can arise when the selected functions or dimensions o
f such standardised measures are not in line with the intervention that is
the focus of the research. Furthermore, the subjective element of quality o
f life makes standardised questionnaires vulnerable to the coping mechanism
, thereby decreasing their sensitivity. The capability approach of the econ
omist and philosopher Amartya Sen offers a descriptive concept that contrib
utes to a better understanding of these problems. This article provides an
introduction to the ideas of Sen for researchers who wish to go beyond the
traditional framework of measuring health-related quality of life.