QWB; the term Index of Well Being or IWB may also be used) was originally developed by Bush and co workers, later largely by Kaplan.Kaplan et al. (1989) characterised the QWB as within the conceptual approach of the SIP and RAND scales, ie. focussed on the impact of disease and disability on function and observable behaviours, such as performance of social role, ability to move around the community, and physical functioning. While developed from a psychometric perspective, Kaplan saw the QWB as providing measures of utility, ie. the Quality of Well Being (QWB) provided a numerical point in time expression of well being that ranges from 0 for death, to 1.0 for optimal functioning.