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Evidence synthesis

19 September 2018

Evidence synthesis is a joint programme of work by the Royal Society and the Academy of Medical Sciences.

‘Evidence synthesis’ refers to the process of bringing together information from a range of sources and disciplines to inform debates and decisions on specific issues. Decision-making and public debate are best served if policymakers have access to the best current evidence on an issue. An accurate, concise and unbiased synthesis of the evidence is therefore one of the most valuable contributions the research community can offer policymakers.

Despite examples of good practice, there remain challenges with both the supply of, and demand for, synthesised evidence. Research funding and evaluation systems often place higher value on original research, and a lack of communication and understanding between policymakers and researchers can create an unintended disconnect between the questions policymakers are asking and the research that has the potential to provide insight.

This report from the Royal Society and the Academy of Medical Sciences outlines the case for evidence synthesis for policy. It then proposes a set of principles that define the fundamental features of good synthesis to inform policymaking. Finally it proposes changes to the research and policy landscapes that would create a more effective marketplace for synthesis. 

The report reflects discussions at two meetings organised by the Royal Society and the Academy of Medical Sciences in 2017, and draws on expertise from a range of disciplines including medicine, natural sciences, social sciences and international development.

The principles for good evidence synthesis are explored in more detail below and a separate fold-out leaflet is available to download (PDF).

For further information please see this Nature Comment from Professor Christl Donnelly FRS and colleagues and the blogs presented below.

The Royal Society and Academy of Medical Sciences are adopting the principles in their own work and will work closely with others to support their use. As part of this, the Royal Society is currently working with RAND Europe to trial the identified principles in a rapid synthesis project on the topic of air quality.

The Royal Society journals now publish evidence synthesis articles. For more information please visit the Proceedings A, Proceedings B and Royal Society Open Science websites.

Air quality synthesis

The Royal Society in collaboration with RAND Europe has undertaken a 3-month rapid synthesis project on air quality to trial the evidence synthesis principles. The report (PDF) provides a synthesis of current evidence on the impacts of ammonia emissions from agriculture on biodiversity. A separate summary document (PDF) highlights the report's key findings.

The agricultural sector is the biggest contributor to ammonia pollution in the UK. As levels of other air pollutants have declined, ammonia emissions in the UK have been rising since 2013, with significant implications for ecosystems and human health. The effects of ammonia emissions on human health are widely acknowledged. However, the environmental impacts of ammonia, despite being a growing concern, are less widely documented.

The report has been submitted to Defra’s Clean Air Strategy consultation. View our consultation response.


  • Inclusive

    Evidence synthesis that involves policymakers throughout and considers many types and sources of evidence is most likely to yield significant policy insights.

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  • Rigorous

    For the evidence synthesis to be robust and reliable, potential sources of bias should be recognised and minimised and the final synthesis article should be independently reviewed.

    Read more

  • Four principles for good evidence synthesis for policy

    These principles for good evidence synthesis for policy have been developed by the Royal Society and the Academy of Medical Sciences, with input from a range of experts.

    Explore the principles

  • Transparent

    Synthesised evidence that is transparent is likely to be more credible, replicable and useful.

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  • Accessible

    For evidence synthesis to be both useful and used it must be accessible. It should be written in plain language and freely available online.

    Read more

Blog posts

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