Understanding Pathways between Agriculture, Food Systems, and Nutrition: An Evidence and Gap Map of Research Tools, Metrics, and Methods in the Last 10 Years

New tools, metrics, and methods in agriculture, food systems, and nutrition (A&N) research proliferated in the decade following the 2007-2008 food price crisis. We map these developments across themes derived from conceptual A&N pathways and expert consultations. We created an interactive Evidence and Gap Map (EGM) from a systematic search of published and gray literature since 2008, following Campbell Collaboration guidelines. We retrieved over 30,000 reports from published literature databases, and individually searched 20 online repositories. We systematically screened 24,359 reports by title and/or abstract, 1577 by full report, and included 904 eligible reports. The EGM consists of rows of thematic domains and columns of types of tools, metrics, and methods, as well as extensive coding applied as filters. Each cell of the map represents research surrounding a type of tool, metric, or method within a given theme. Reports in each cell are grouped by stage of development, which expand to a corresponding bibliography. Users can filter EGM reports by various characteristics. The 4 most populated domains were: diets, nutrition, and health; primary food production; water, sanitation, and hygiene; and environment and sustainability. The 4 most common types of metrics, methods, and tools were: diet metrics; footprint analysis (especially water); technology applications; and network or Bayesian analysis. Gaps represent areas of few or no reports of innovation between 2008 and 2018. There were gaps in reports and innovations related to: power or conflicts of interest; food environments; markets; private sector engagement; food loss and waste; conflict; study design and system-level tools, metrics, and methods. The EGM is a comprehensive tool to navigate advances in measurement in A&N research: to highlight trends and gaps, conduct further synthesis and development, and prioritize the agenda for future work. This narrative synthesis accompanies the EGM, which can be found at https://www.anh-academy.org/evidence-and-gap-map.