Quality Adjusted Life Years (QALYs)
QALYs is a measure of the benefit of a medical intervention. It is based on the number of years of life that would be added by the intervention. Each year in perfect health is assigned the value of 1.0 down to a value of 0 for death. If the extra years would not be lived in full health, for example if the patient would lose a limb, or be blind or be confined to a wheelchair, then the extra life-years are given a value between 0 and 1 to account for this.
QALYs are controversial as the measurement is used to calculate the allocation of healthcare resources based upon a ratio of cost per QALY. As a result, some people will not receive treatment as it is calculated that the benefits to their quality of life do not justify expenditures involved.