While it is generally accepted that QoL is a multidimensional concept and that the core domains tap into
physical, psychological, cognitive and social aspects of
functioning it is still the case that different QoL measures
define these domains in different ways and then go on to
divide them up into different sub-domains. As a consequence there is a considerable degree of inter-instrument
non-overlap and we cannot simply assume equal coverage
by different measures or that all generic QoL measures
cover the necessary ground. This often makes it difficult to