Evidence synthesis of population health interventions: syntheses and advancing methods

Abstract

Evidence synthesis of population health interventions often involves managing data from complex interventions and a diverse range of study designs, presenting challenges in applying synthesis methods to provide meaningful results. The work presented here provides examples of population health syntheses and research aimed at improving the conduct and reporting of both synthesis methods and primary studies that are used in syntheses. An initial essay provides a background on population health intervention evaluations and considers the implications, challenges and value of synthesising population health evidence. An overview of methods to develop guidance examines approaches to achieving consensus and the importance of supporting and managing the project team during guidance development. Three themes address evidence synthesis of population health interventions. In Theme 1, two reviews demonstrate the use of appropriate methods rigorously applied to population health evidence. The reviews examined the health impacts of social policies, mandatory participation in employment related programmes and participatory budgeting. Conducting these and other reviews developed my experience and ability to contribute to the projects in the following two themes. Theme 2 discusses three papers that advance systematic review methods by investigating and developing guidance on how to conduct and report synthesis robustly and transparently. The first paper provides guidance for conducting a systematic review of theories, illustrated and discussed using a worked example. The remaining two papers focus on narrative synthesis methods in systematic reviews. One is a methodological study to determine the adequacy of reporting of narrative synthesis of quantitative data in systematic reviews of population health interventions. This led to the third paper, guidance for reporting synthesis without meta-analysis (SWiM), an explanation and elaboration of nine checklist items designed to prompt systematic review authors to include key information when reporting the synthesis of quantitative effect data. Theme 3 consists of two sets of methodological guidance developed for reporting and conducting population health studies, both relevant for evidence synthesis. TIDieR-PHP is a guideline for reporting population health and policy interventions. Precise descriptions of interventions are crucial for synthesis and TIDieR-PHP prompts users on how to capture the features of interventions that are delivered to, or experienced by, large groups or populations, such as the policies examined in Theme 1. The second paper is guidance for using natural experiments to evaluate population health interventions. The guidance aims to prompt improved conduct and reporting of population health interventions, which is crucial to synthesising evidence of these interventions