Article type
Abstract
Background: Policymaking concerning environmental exposures is plagued by several problems. Evidence synthesis methods to evaluate the effect of complex environmental exposures on health remain nascent. Misapplication of methods appropriate for clinical synthesis hampers effective policy development. Workload demand on policy agencies to create rigorous evidence synthesis hampers the timely production of policy-informing syntheses. Policymaking bodies must prioritize evidence synthesis efforts, often without the benefit of knowledge of whether evidence is available.
Objective: Describe the methods and process for the creation of Weight of Evidence (WoE) syntheses across multiple streams of evidence of complex environmental exposures and health. The goal is to introduce an evidence synthesis pipeline that nimbly integrates multiple questions, providing an overall synthesis to guide policy decision-making.
Method: We modified an online platform to create a process that allows for screening, extraction, and synthesis of multiple evidence synthesis questions simultaneously. This creates an evidence synthesis “pipeline” accommodating multiple topics. We adapted and synthesized Cochrane, US Environmental Protection Agency, and World Health Organization evidence synthesis methods within a WoE approach. We developed a novel approach to evaluating strength of evidence, which incorporates evidence for alternative explanations. Eppi Mapper was integrated.
Results: Four evidence streams (epidemiological, clinical, molecular, civilian), encompassing a framework of 12 distinct PECOT questions (population, exposure, comparison, outcome, timing), were synthesized (Figure 1). N = 192 articles were extracted, evaluated for risk of bias, and a strength of evidence rating was assigned to each of the PECOT questions. A final WoE conclusion was developed. Random effects meta-analyses were used when appropriate for data synthesis. An evidence map was created to facilitate prioritization of future projects.
Conclusion: In contrast to the standard approach of completing each evidence synthesis before moving to the next, we developed a pipeline approach that allows for multiple questions to be asked and multiple project phases to be carried out simultaneously. New questions can be integrated into existing workflows without waiting for the previous project's completion. Pulling from multiple evidence streams provides the ability draw conclusions while scoping the literature. This provides a basis for decision-making and prioritization of future projects by policymakers.
Objective: Describe the methods and process for the creation of Weight of Evidence (WoE) syntheses across multiple streams of evidence of complex environmental exposures and health. The goal is to introduce an evidence synthesis pipeline that nimbly integrates multiple questions, providing an overall synthesis to guide policy decision-making.
Method: We modified an online platform to create a process that allows for screening, extraction, and synthesis of multiple evidence synthesis questions simultaneously. This creates an evidence synthesis “pipeline” accommodating multiple topics. We adapted and synthesized Cochrane, US Environmental Protection Agency, and World Health Organization evidence synthesis methods within a WoE approach. We developed a novel approach to evaluating strength of evidence, which incorporates evidence for alternative explanations. Eppi Mapper was integrated.
Results: Four evidence streams (epidemiological, clinical, molecular, civilian), encompassing a framework of 12 distinct PECOT questions (population, exposure, comparison, outcome, timing), were synthesized (Figure 1). N = 192 articles were extracted, evaluated for risk of bias, and a strength of evidence rating was assigned to each of the PECOT questions. A final WoE conclusion was developed. Random effects meta-analyses were used when appropriate for data synthesis. An evidence map was created to facilitate prioritization of future projects.
Conclusion: In contrast to the standard approach of completing each evidence synthesis before moving to the next, we developed a pipeline approach that allows for multiple questions to be asked and multiple project phases to be carried out simultaneously. New questions can be integrated into existing workflows without waiting for the previous project's completion. Pulling from multiple evidence streams provides the ability draw conclusions while scoping the literature. This provides a basis for decision-making and prioritization of future projects by policymakers.