Series: Clinical Epidemiology in South Africa. Paper 3: Logic models help make sense of complexity in systematic reviews and health technology assessments

Objective To describe the development and application of logic model templates for systematic reviews and health technology assessments (HTAs) of complex interventions. Study Design and Setting This study demonstrates the development of a method to conceptualize complexity and make underlying assumptions transparent. Examples from systematic reviews with specific relevance to Sub-Saharan Africa (SSA) and other low- and middle-income countries (LMICs) illustrate its usefulness. Results Two distinct templates are presented: the system-based logic model, describing the system in which the interaction between participants, intervention, and context takes place; and the process-orientated logic model, which displays the processes and causal pathways that lead from the intervention to multiple outcomes. Conclusion Logic models can help authors of systematic reviews and HTAs to explicitly address and make sense of complexity, adding value by achieving a better understanding of the interactions between the intervention, its implementation, and its multiple outcomes among a given population and context. They thus have the potential to help build systematic review capacity—in SSA and other LMICs—at an individual level, by equipping authors with a tool that facilitates the review process; and at a system-level, by improving communication between producers and potential users of research evidence.