Using theory to synthesise evidence from behaviour change interventions: The example of audit and feedback Benjamin Gardner a, * , Craig Whittington a , John McAteer a , Martin P. Eccles b , Susan Michie a a Centre for Outcomes Research and Effectiveness, University College London, 1e19 Torrington Place, London WC1E 7HB, UK b Newcastle University, UK article info Article history: Available online 16 February 2010 Keywords: Theory Health psychology Evidence synthesis Review Meta-analysis Meta-regression Behaviour change Audit and feedback Interventions abstract Evidence syntheses are used to inform health care policy and practice. Behaviour change theories offer frameworks for categorising and evaluating interventions and identifying likely mechanisms through which effects are achieved. Yet systematic reviews rarely explicitly classify intervention components using theory, which may result in evidence syntheses and health care practice recommendations that are less than optimal. This paper outlines a method for applying theory to evidence syntheses of behaviour change interventions. We illustrate this method with an analysis of ‘audit and feedback’ interventions, based on data from a Cochrane review. Our analysis is based on Control Theory, which suggests that behaviour change is most likely if feedback is accompanied by comparison with a behavioural target and by action plans, and we coded interventions for these three techniques. Multivariate meta-regression was performed on 85 comparisons from 61 studies. However, few interventions incorporated targets or action plans, and so meta-regression models were likely to be underfitted due to insufficient power. The utility of our approach could not be tested via our analysis because of the limited nature of the audit and feedback interventions. However, we show that conceptualising and categorising interventions using behaviour change theory can reveal the theoretical coherence of interventions and so point towards improvements in intervention design, evaluation and synthesis. The results demonstrate that a theory- based approach to evidence synthesis is feasible, and can prove beneficial in understanding intervention design, even where there is insufficient empirical evidence to reliably synthesise effects of specific intervention components. Ó 2010 Elsevier Ltd. All rights reserved. Scientific evidence is used to inform healthcare policy and prac- tice. The US Preventive Services Task Force, for example, operates to synthesise evidence as a basis for public health interventions and policy. In England and Wales, the National Institute for Health and Clinical Excellence (NICE) provides guidance on health care based on systematic reviews of research evidence, and health professionals and commissioners are expected to use NICE guidelines to inform professional practice and health service provision. The role of research evidence in modernising and facilitating high quality health services has been further emphasized in recent appraisals of the UK National Health Service (Darzi, 2008a), and there have been calls for greater investment in the systematic review process to improve patient and public health outcomes (Darzi, 2008b). For the potential of this investment to be fully realized, methods of evidence synthesis must be able to achieve the best summary to inform health care practice. Behaviour change interventions, however, are often complex and multifaceted (Craig et al., 2008), requiring the devel- opment of methods for systematic identification, quantification, theoretical understanding and synthesis of the effects of interven- tion components. Using theory to synthesise evidence from behaviour change interventions Behaviour change theories represent integrated summaries of hypothesized causal processes, and so offer a standardized and systematic framework for categorising and evaluating intervention content. Applying theory to evidence synthesis allows scientific knowledge about behaviour change to be used in specifying inter- vention techniques and likely mechanisms by which any effects are achieved. Theory-based explanations offer explicit causal pathways and so avoid use of implicit assumptions regarding the causal determinants of behaviour change (Johnston, 1995; Michie & Abraham, 2004). Behaviour change theories rarely specify which techniques should be used to change behaviour; this requires both a method of * Corresponding author. Tel.: þ44 207 679 8267. E-mail address: b.gardner@ucl.ac.uk (B. Gardner). Contents lists available at ScienceDirect Social Science & Medicine journal homepage: www.elsevier.com/locate/socscimed 0277-9536/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.socscimed.2010.01.039 Social Science & Medicine 70 (2010) 1618e1625