This paper seeks to highlight some of the critical issues concerning the use of the Quality Adjusted Life Years (QALYs) to measure the outcome of health care choices, in decisions related to both individual patient care and social resource allocation. Much of the support for the QALY is based on its simplicity as a tool for resolving complex choices. However, it may be the case that the QALY is not sufficiently refined or robust, failing perhaps to take into account some of the critical factors which affect preferences over different health care scenarios.