These interventions can take a variety of forms - from targeted ad campaigns to educational workshops designed to inform the public about steps they can take to improve their health. MRC guidance argues that only through close scrutiny of causal mechanisms is it possible for evaluation to contribute to developing more effective interventions, and provide insights into how findings might be transferred across settings and populations. One of the most important tools available to public health practitioners is the intervention.

We aimed to assess how a systems approach could be applied in the context of public health evaluation.

This important resource offers an overview of the history, purpose, strengths, and limitations of process evaluation and includes illustrative case material of the current state of the art in process evaluation. In the first contribution to a new section in AJPH that will address critical methodological issues in evaluations of public health interventions, I will discuss topics in study design and analysis, covering the most innovative emerging methodologies and providing an overview of best practices. The methods considered are motivated by public health evaluations, both domestic and global. There has been a growth in interest in applying systems thinking to public health research, including greater consideration of the complex and changing nature of real-world environments where public health interventions take place. Public health interventions tend to be complex, programmatic, and context dependent. The evidence for their effectiveness must be sufficiently comprehensive to encompass that complexity. Public health organizations must continually improve upon the standards of evidence used in the evaluation of public health so that results can inform managerial and policy decision making.