Three broad movements are seeking to change the world of medicine. The proponents of ‘evidence-based medicine’ are mainly concerned with ensuring that strategies of proven clinical effectiveness are adopted. Health economists are mainly concerned to establish that ‘cost-effectiveness’ and not ‘clinical effectiveness’ is the criterion used in determining option selection. A variety of patient support and public interest groups, including many health economists, are mainly concerned with ensuring that patient and public preferences drive clinical and policy decisions. This paper argues that decision analysis based medical decision making (DABMDM) constitutes the pre-requisite for the widespread introduction of the main principles embodied in evidence-based medicine, cost-effective medicine and preference-driven medicine; that, in the light of current modes of practice, seeking to promote these principles without a prior or simultaneous move to DABMDM is equivalent to asking the cart to move without the horse; and that in fact DABMDM subsumes and enjoins the valuable aspects of all three. Particular attention is paid to differentiating between DABMDM and EBM, by way of analysis of various expositions of EBM and examination of two recent empirical studies. EBM, as so far expounded, reflects a problem-solving attitude that results in a heavy concentration on RCTs and meta-analyses, rather than a broad decision making focus that concentrates on meeting all the requirements of a good clinical decision. The latter include: Ensuring that inferences from RCTs and meta-analyses to individual patients (or patient groups) are made explicitly; paying equally serious attention to evidence on values and costs as to clinical evidence; and accepting the inadequacy of ‘taking into account and bearing in mind’ as a way of integrating the multiple and distinct elements of a decision.

A theory-based instrument for measuring the quality of decisions made using any form of decision technology, including both decision-aided and unaided clinical consultations is required to enable person- and patient-centred care and to respond positively to individual heterogeneity in the value aspects of decision making. Current instruments using the term ‘decision quality’ have adopted a decision- and thus condition-specific approach. We argue that patient-centred care requires decision quality to be regarded as both preference-sensitive across multiple relevant criteria and generic across all conditions and decisions. MyDecisionQuality is grounded in prescriptive multi criteria decision analysis and employs a simple expected value algorithm to calculate a score for the quality of a decision that combines, in the clinical case, the patient’s individual preferences for eight quality criteria (expressed as importance weights) and their ratings of the decision just taken on each of these criteria (expressed as performance rates). It thus provides an index of decision quality that encompasses both these aspects. It also provides patients with help in prioritizing quality criteria for future decision making by calculating, for each criterion, the Incremental Value of Perfect Rating, that is, the increase in their decision quality score that would result if their performance rating on the criterion had been 100%, weightings unchanged. MyDecisionQuality, which is a web-based generic and preference-sensitive instrument, can constitute a key patient-reported measure of the quality of the decision-making process. It can provide the basis for future decision improvement, especially when the clinician (or other stakeholders) completes the equivalent instrument and the extent and nature of concordance and discordance can be established. Apart from its role in decision preparation and evaluation, it can also provide real time and relevant documentation for the patient’s record.

The arrival of new analysis-based decision technologies will necessitate a profound rethinking both of the nature of the patient–doctor relationship and of the way aids and support systems designed to improve decision-making within that relationship are designed and evaluated. One-dimensional typologies of the traditional `paternalist/shared/informed' sort do not provide the complexity called for by the heterogeneity of patient's `meta-preferences' regarding their relationship with a doctor on the one hand and regarding the analytical level of judgement and decision-making on the other. A multidimensional matrix embodying this distinction is proposed as a framework of the minimal complexity required for the design and evaluation of the full range of decision aids and decision modes. Essentially aids should be conceived of and evaluated cell-specifically and the search for universally satisfactory decision support systems abandoned. `shared' and `informed' are best interpreted as attributes which may or not be in line with a patient's meta-preferences. Future research should focus on the higher level goal of better decision-making, a goal that will need to respect and reflect these meta-preferences.