Outcome measurement in complementary and alternative medicine: unpicking the effects.

The issues of what outcomes to measure and how this is central to the development of a sound knowledge base for evidence-based practice are examined. Within complementary and alternative medicine (CAM) there is a crucial debate over what is meant by an "effect" of a set of CAM treatment sessions. The goal of this paper is promote debate and reflection on why outcome measurement is important, the range of specific effects that need to be measured, and ways to take forward their measurement. It is argued that monitoring the achievement of desired outcomes needs to be recognized as an essential step in evidence-based practice, with effectiveness, achieved effects/outcomes--both positive and negative--and quality assurance inextricably linked together in an evidence spiral. The choice of outcome measures must also match the desired outcomes of the key participants, specifically those of the user. Three types of effects of a CAM intervention are conceptualized: (1) those arising from the philosophy and practice of health and healing; (2) factors arising from the relationship between user and practitioner: and (3) those factors brought about by the set of techniques used to enhance the healing process. Their conceptual separation clarifies what should be measured and raises questions about the adequacy of available measuring instruments. This delineation of effects has relevance beyond CAM to conventional medicine and discussions over the nature of the placebo effect. Measurement of all three types of effect is essential, in research and in practice, if the full effect of a CAM discipline is to be recognized. Further work is needed to develop and validate measures that address the multiple effects of CAM and to explore the nature and form of the three types of effect within different CAM disciplines.