J Manipulative Physiol Ther. 1998 Jul-Aug; 21(6): 402-9.

Strong and weak measures of efficacy: a comparison of chiropractic with biomedicine in the management of back pain.

Anderson R.

Department of Sociology and Anthropology, Mills College, Oakland, California 94613-1301, USA.

A holistic, biocultural model for identifying efficacy in the management of back pain by chiropractic and medical doctors is proposed based on adopting the concepts of vertical reasoning and dual-level control. Using this approach, four different ways in which efficacy can be measured are identified: (a) anatomical-physiological (curing of disease), (b) body/mind (healing of illness), (c) sociocultural (termination of sickness) and (d) political-economic (ending no access to care). These four are conceptualized as relating to levels in a hierarchy of structures of increasing size and complexity ranging from atoms and molecules to societies and nations. In measuring efficacy at each level, it is important to distinguish weak from strong measures. Strong measures conform to a Guttman scale model; each higher measure of efficacy also demonstrates efficacy at all levels lower than itself. Weak measures fail to conform to a Guttman-like scale, and are therefore of questionable value when used to support decisions relating to health care policy.