Building an evidence base for healthcare interventions has long been advocated as both professionally and ethically desirable. By supporting meaningful comparison amongst different approaches, a good evidence base has been viewed as an important element in optimising clinical decision-making and the safety and quality of care. Unsurprisingly, medical research has put considerable effort into supporting the development of this evidence base, and the randomised controlled trial has become the dominant methodology. Recently however, a body of research has begun to question, not just this methodology per se, but also the extent to which the evidence it produces may marginalise individual patient experiences, priorities and perceptions.Simultaneously, the widespread adoption and utilisation of information systems (IS) in health care has also prompted initiatives to develop a stronger base of evidence about their impacts. These calls have been stimulated both by numerous system failures and research expressing concerns about the limitations of information systems methodologies in health care environments. Alongside the potential of information systems to produce positive, negative and unintended consequences, many measures of success, impact or benefit appear to have little to do with improvements in care, health outcomes or individual patient experiences.Combined these methodological concerns suggest the need for more detailed examination. This is particularly the case, given the prevalence within contemporary clinical and IS discourses on health interventions advocating the need to put the 'patient at the centre' by engaging them in their own care and/or 'empowering' them through the use of information systems.This paper aims to contribute to these on-going debates by focusing on the socio-technical processes by which patients' interests and outcomes are measured, defined and evaluated within health interventions that involve them using web-based information systems. The paper outlines an integrated approach that aims to generate evidence about the impact of these types of health interventions that are meaningful at both individual patient and patient cohort levels.
Keywords: Patients; evaluation; evidence; health information systems; web-based systems..