Four principles for synthesizing evidence

Depending on its focus and purpose, synthesis may consider evidence of many kinds, including quantitative and qualitative data, published and unpublished academic literature, research conducted by industry or by non-governmental organizations, policyevaluation studies from many countries and contexts, and expert and public opinion. The Campbell Collaboration (www.campbellcollaboration.org) provides a similar service for decision-making in education, social welfare, crime and justice, and international development, with reviews on topics including school start times, therapies for sexual offenders, and handwashing and sanitation behaviours in low- and middleincome countries. In both cases, co-ordinating groups manage the process in a way that minimizes bias - involving predefined methodologies, training for authors, peer review and often a significant amount of time. To catalyse the necessary changes in the United Kingdom, the following organizations will promote and adopt the principles: the Royal Society, the Academy of Medical Sciences, UK Research and Innovation (UKRI), the Government Office for Science, the Department for Environment, Food and Rural Affairs, the Department of Health and Social Care and the UK Civil Service Policy Profession (an informal network for civil servants who work on government policymaking).