Protocol for a Crowd-Sourced Living Global Directory of Grey Literature Sources for Systematic Reviews of Evaluations of Climate Solutions

Under intensifying climate risks, national and international policy assessments face growing pressure to engage with rapidly expanding and complex bodies of evidence. Systematic reviews are increasingly occupying a central role in supporting such assessments, using structured and transparent methods of evidence identification and appraisal to consolidate findings from evaluations of the impacts of climate-related policies, programmes, and interventions. However, comprehensive identification of relevant evaluation evidence remains a persistent methodological challenge, particularly where studies are disseminated through grey literature sources that are not indexed in academic databases (such as many government evaluation reports, foundation-commissioned research, and evaluations produced by private and third-sector organisations). Based on expert-developed resources, current guidance and resources to support searching for grey literature is not comprehensive, can become quickly outdated, and does not reflect the full range of potential grey literature sources, instead tending to provide information on more visible and internationally recognised organisations. This research proposes to explore the development of a crowd-sourced, living global directory to inform understanding of the range of different of grey literature sources that exist on evaluations of climate solutions, and how these sources are distributed according to type and geographic context. Based on a community contribution model and the principle of collective knowledge (or the “wisdom of the crowd”), the approach seeks to aggregate knowledge distributed from individuals across the globe, who are embedded in diverse policy and geographic contexts. This recognises that awareness about where evaluation evidence resides can be locally or institutionally held. This protocol outlines the inclusion criteria, identification strategy, and classification framework guiding the development of the directory, as well as the subsequent planned analysis of its findings.