Evaluation of the effects of health care systems and their changes on health status

Abstract

The concept of “effect” is defined, and the complexity of its evaluation is pointed out. The relevant method is explained: a health care system can be appraised by comparing its changes and those of the expected changes in the health status of the population, both in time and in space. Ways of avoiding wrong attributions of causality are presented, as well as ways of consolidating proof of an hypothetical effect through the accumulation of circumstantial evidence. The mechanism whereby an effect is induced by a system is analyzed. The objectives of effect evaluation are mentioned. On the basis of literature review and of observation in the field of effects evaluation, some of the lessons that can be learnt are noted.