What is good evidence?

Evidence-based interventions or programmes are those which have been proven effective in multiple, high-quality randomised controlled trials (RCTs).

However, the label ‘evidence-based’ is used (and often mis-used) to describe a vast range of programmes that have undergone varying degrees of evaluation. It can describe programmes that have been implemented with thousands of people and evaluated in numerous RCTs; undergone only a single follow-up survey with a few participants; or anything in between.



Systematic reviews gather all research evidence about a specific topic, and synthesise and appraise that evidence, to address a specific research question. As its name suggests, this method is systematic – it aims to identify and appraise all relevant evidence, based on specific criteria, to minimise bias.

Two of the best sources for good systematic reviews are the Cochrane Collaboration and the Campbell Collaboration. Other sources

How to know if a systematic review is of good quality and worth reading