The application of the complexity theory to public health interventions: a review of the literature

Abstract

Abstract Background There is a growing recognition of the limitations of a linear cause-and-effect rationality in planning and evaluating public health interventions. Although this perspective is amenable to programme planning and evaluation, it leaves aside a whole array of mechanisms of change triggered by interactions taking place in complex social systems. Generative causality is one and recognized under a number of works referring to the complexity paradigm. Here we review the state of knowledge on what is often referred to as the complexity theory (CT), and present the results of a review of the literature on its application in public health. Methods We searched PubMed for articles, commentaries, editorials published in English, French and Italian, using the keywords 'Complexity Theory' (also plural). We categorized the fields of application of the CT according to the three core WHO's Essential Public Health Operations, i.e., Health Promotion, Prevention and Protection. All papers addressing issues related to health care services (but not prevention) were included in the category “health care services” while others were tagged as “others”. Results We found 203 papers meeting our inclusion criteria. The largest share of the research output applying the CT was in health care services (n = 167), followed by Health Promotion (5), Prevention (3) and Protection (2). 26 papers were labelled others. In health promotion/ prevention, applications of the CT have yet to integrate most of its concepts. Most authors tap into both the linear and generative rationality perspectives. Conclusions Although regularly deemed as promising in uncovering mechanisms for change triggered by public health intervention, applications of the complexity theory remain uncommon and has made little inroads in the public health domain. This is particularly the case for health promotion where one would assume that participatory community-based interventions would be an incentive to integrate this perspective. Key messages Although deemed promising the complexity theory has made little inroads in public health. Health promotion with its participatory community-based interventions can benefit from its application.