The design of patient decision support interventions: addressing the theory–practice gap Glyn Elwyn BA MB BCh MSc PhD FRCGP, 1 Mareike Stiel, 2 Marie-Anne Durand PhD 3 and Jacky Boivin PhD 4 1 Professor, 3 Research Associate, Clinical Epidemiology Interdisciplinary Research Group, Department of Primary Care and Public Health, School of Medicine, Cardiff University, Heath Park, Cardiff, UK 2 Doctoral Candidate, 4 Professor, Cardiff Fertility Studies Research Group, School of Psychology, Cardiff University, Cardiff, UK Keywords decision aids, decision-making theory, DESIs, operationalization Correspondence Professor Glyn Elwyn Department of Primary Care and Public Health School of Medicine Cardiff University Heath Park Cardiff CF14 4YS UK E-mail: elwyng@cardiff.ac.uk Accepted for publication: 11 June 2010 doi:10.1111/j.1365-2753.2010.01517.x Abstract Background Although an increasing number of decision support interventions for patients (including decision aids) are produced, few make explicit use of theory. We argue the importance of using theory to guide design. The aim of this work was to address this theory–practice gap and to examine how a range of selected decision-making theories could inform the design and evaluation of decision support interventions. Methods We reviewed the decision-making literature and selected relevant theories. We assessed their key principles, theoretical pathways and predictions in order to determine how they could inform the design of two core components of decision support interven- tions, namely, information and deliberation components and to specify theory-based outcome measures. Results Eight theories were selected: (1) the expected utility theory; (2) the conflict model of decision making; (3) prospect theory; (4) fuzzy-trace theory; (5) the differentiation and consolidation theory; (6) the ecological rationality theory; (7) the rational–emotional model of decision avoidance; and finally, (8) the Attend, React, Explain, Adapt model of affective forecasting. Some theories have strong relevance to the information design (e.g. prospect theory); some are more relevant to deliberation processes (conflict theory, differentiation theory and ecological validity). None of the theories in isolation was sufficient to inform the design of all the necessary components of decision support interventions. It was also clear that most work in theory-building has focused on explaining or describing how humans think rather than on how tools could be designed to help humans make good decisions. It is not surprising therefore that a large theory–practice gap exists as we consider decision support for patients. There was no relevant theory that integrated all the necessary contri- butions to the task of making good decisions in collaborative interactions. Discussion Initiatives such as the International Patient Decision Aids Standards Collabo- ration influence standards for the design of decision support interventions. However, this analysis points to the need to undertake more work in providing theoretical foundations for these interventions. Introduction When Lewin proposed that ‘nothing is as practical as a good theory’ he was emphasizing the value of hypothesis-led experi- mentation to advance understanding [1]. When considering deci- sion support interventions (DESIs) for patients (including decision aids), there remains significant potential to improve our under- standing of why and how they achieve their impact on patients’ knowledge and their participation in decision making [2]. Holmes- Rovner et al. [3] and Nelson et al. [4] have questioned the overall aims of ‘decision aids. Charles et al. has requested greater con- ceptual clarity [5]. Achieving greater clarity about the relationship between theory and practice in this field will help address a number of outstanding debates about the relationship between design, deliberation process and outcome measurement [4–10]. O’Connor et al. defined decision aids as: ‘interventions designed to help people make specific and deliberative choices among options by providing information about the options and outcomes that are relevant to a person’s health status’ [11]. In 2009, Elwyn et al. went further and stated that: ‘DESIs help Journal of Evaluation in Clinical Practice ISSN 1356-1294 © 2010 Blackwell Publishing Ltd, Journal of Evaluation in Clinical Practice 1