The 'Evidence Movement'
Seeking of evidence to support public policy decisions is not new. However, formal approaches and systematic methods for appraising and collating evidence have been developed in recent decades. This has been in response to calls from the 'evidence movement' to organise knowledge into a useable and reliable format.
Critical appraisal and synthesis of research findings in a systematic manner emerged in its first formal guise in 1975 under the term 'meta analysis'. The phrase was coined by Glass who conducted syntheses in the areas of psychotherapy (Smith, Glass and Miller 1980) and class size (Glass and Smith 1979).
Although these early syntheses were conducted in broader areas of public policy and social interventions, initially, systematic research synthesis was applied to medicine and health. Archie Cochrane's seminal text 'Effectiveness and efficiency' (1972) urged health practitioners to practice evidence based medicine, later defined by Professor David Sackett as ‘the conscientious, explicit, judicious use of current best evidence in making decisions about the care of individual patients.' (Sackett et al 1996)
Supporting evidence-based medicine - The Cochrane Collaboration
In the late 1970s and early 1980s a group of health service researchers in Oxford prepared the ground for evidence-based medicine by beginning a programme of systematic reviews on the effectiveness of health care interventions. The Cochrane Collaboration opened its centre in Oxford in 1992 and is now an international network of researchers, academics, practitioners and users committed to the principles of managing healthcare knowledge in such a way that it is quality assured, accessible, and cumulative.
Moving beyond medicine - the Campbell Collaboration
It was soon recognised that facilities for reviews in areas beyond health were called for and a sibling organisation to Cochrane, the Campbell Collaboration, emerged. The Campbell Collaboration adapted Cochrane methodology to bring the same quality of systematic evidence to issues of broader public policy.
Beyond effectiveness reviews - The EPPI Centre
The EPPI Centre developed from a project set up by Ann Oakley in 1992 at the Social Science Research Unit, Institute of Education, University of London. This project aimed to develop a database of well designed evaluations of interventions in the fields of education and social welfare. In 1995 the department of health commissioned a series of reviews in the area of health promotion to mirror the work of Cochrane in the field of non-clinical health issues, thus the EPPI Centre was born.
The need for a more strategic approach to the accumulation and use of educational research was argued for by David Hargreaves, then adviser to government ministers on education, in his famous 1996 TDA lecture*. This fitted well with the EPPI Centre's approach to user led systematic reviews concerned with all questions and types of research evidence.
The remit of the EPPI Centre was further broadened in 2000 by gaining support from the Department for Education and Skills to support groups wishing to undertake reviews in the field of education. Some work was also funded by the Training and Development Agency for Schools. The Centre now also undertakes reviews in social care for the Social Care Institute for Excellence and in employment for the Department for Work and Pensions.
The methodology, expertise and tools have developed within the EPPI Centre. Reviews are now being undertaken in many fields, appraising and synthesising a broad range evidence for all research questions and thus potentially to include all types of study. Our methods work has been strengthened by becoming the Methods for Research Synthesis node of the ESRC National Centre for Research Methods.
For a full account of the evolution of systematic research synthesis and the EPPI Centre, see Oakley et al (2005). For an account of the development of evidence-based medicine, see Sackett et al (1996).
Cochrane AL (1972) Effectiveness and efficiency: random reflections on health services. London: Royal Society of Medicine Press.
Glass GV, Smith ML (1979) Meta-analysis of research on the relationship of class-size and achievement. Educational Evaluation and Policy Analysis 1: 2-16.
Oakley A et al (2005) The politics of evidence and methodology: lessons from the EPPI Centre. Evidence & Policy 1 (1): 5–31.
Sackett DL et al (1996) Evidence based medicine: what it is and what it isn't. British Medical Journal 312: 71-2.
Smith M, Glass G, Miller T (1980) The benefits of psychotherapy. Baltimore, MD: Johns Hopkins University Press.