Understanding evidence based public health policy and practice: an Actor Network Theory analysis

Despite widespread acceptance that public health decisions should be based on evidence the reality is that the use of research evidence in public health policy and practice has been low. Studies investigating the factors that act to limit the implementation of research evidence in public health practice often point to the gap between the research and its use in practice. This gap is thought be a function of the availability and quality of the evidence, individual and organisational capabilities and the context in which it is interpreted. The direct transfer of research evidence in the public health domain is complicated by uncertainty about the effectiveness of interventions when transferring what works in one community to another; problems of attributing causal mechanisms when it is known that other policy decisions also impact on health outcomes and the long time delays before the results of a public health intervention can be observed. In addition public health decision making is subject to other factors such as political influences, financial and resources constraints, public pressure and the views of the community. This thesis used Actor Network Theory (ANT) as a framework to determine how the use of evidence by public health organisations was influenced by the quality of the evidence itself and by contextual factors identified by ANT. Six case studies covering a number of public health issues; climate change, tobacco control, syndromic surveillance for outbreak detection, health needs assessments and health literacy, were used in the analysis. ANT revealed the mechanism by which many of the barriers previously identified in the literature impacted on the translation of evidence into public health policy and practice. The model showed the role that external factors such as the media and public opinion play in the decision making process. It also showed how competing networks, such as lobby groups, can act to influence policy decisions. The quality of the evidence was pivotal in mobilising the policy idea in these case studies; where it was weak or surrounded by considerable uncertainty the policy ideas did not garner support. Finally ANT was able to demonstrate how features of the organisation may impact on the use of evidence in public health practice and how the forging of alliances may provide a mechanism to overcome these limitations. The ANT framework has assisted our understanding of how research evidence is translated into policy and practice. This knowledge should improve the translation process, lead to greater use of evidence in public health practice and ultimately to more robust public health interventions.