The degree to which a treatment plan, programme or project has achieved its purpose within the limits set for reaching its objective. For example, an expression of the desired effect of a programme, service or institution in reducing a health problem or improving an unsatisfactory health situation.
n. measures that are used in health economics and ethics to assess treatments of all kinds. A treatment that works or achieves its object is effective, but may do so at great cost. If it is also efficient, it achieves its aim equally but at lower cost (or consumes less resources) when compared with other treatments. Such an assessment may be part of an *intervention study. Even apparently effective and efficient treatments may work for patients only by depriving others of similar care (opportunity costs), so a moral evaluation must take into account the overall aims and purposes of health care in general.... effectiveness and efficiency
Health Encyclopedia