Methods development in evidence synthesis: a dialogue between science and society

This chapter is about the science of evidence synthesis: the way that academics bring together knowledge from across multiple studies into a whole, to present the state of current understanding about a given area. While scientists have been doing this for centuries in the form of literature reviews, the advent of ‘evidence informed’ decision-making over the past 30-40 years has forced academics to develop a form of literature review that was demonstrably the sum of available knowledge in its area (rather than providing a partial and potentially biased picture). The key challenge methodologically has been in providing useful and useable evidence that can inform decisions, whilst not compromising on the high standards that usually need to be met to make claims about causality. Addressing this challenge has required the evolution of new research methods across multiple disciplines - something that seems likely to continue into the future.