About This Guide

This research guide was developed for NOAA employees and provides an overview of evidence synthesis and its application to evidence-based policy and decision-making. The guide includes information on processes and guidelines to assist in planning, conducting, and reporting evidence synthesis research.

What is Evidence Synthesis?

Evidence Synthesis is an umbrella term that encompasses various methods that seek to systematically identify, compile, and combine available evidence to answer a specific research question or map the available evidence of a particular topic. These methods follow established guidelines and standards to increase transparency, reduce bias, and improve the reliability and trustworthiness of the findings. The two most common methods of synthesis are systematic reviews and systematic maps, which serve distinct needs. Systematic Reviews analyze the impact of an action, while Systematic Maps examine the distribution of abundance (or gaps) in the evidence base. Compared to traditional literature reviews, these methods provide a more rigorous review of the available evidence. 

Why Evidence Synthesis?

In both research and policymaking, evidence synthesis can be an important tool in making sense of the vast amounts of published research by distilling it into practical insights and providing confidence that the best available science has been consulted. The ultimate goal in applying evidence synthesis methods is to ensure more strategic, informed, and evidence-based decision-making. When decisions are based on a full and transparent review of the best available evidence, this can lead to more accurate, reliable, and effective decisions, policies, and outcomes. By applying evidence synthesis methods, decision-makers can also minimize the risk of costly errors due to incomplete information, more efficiently allocate funding, direct actions towards filling critical knowledge gaps, and increase the likelihood of successful outcomes.