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BACKGROUND Stepped wedge randomised trial designs involve sequential roll-out of an intervention to participants (individuals or clusters) over a number of time periods. By the end of the study, all participants will have received the intervention, although the order in which participants receive the intervention is determined at random. The design is(More)
BACKGROUND Cluster randomised controlled trials (CRCTs) are frequently used in health service evaluation. Assuming an average cluster size, required sample sizes are readily computed for both binary and continuous outcomes, by estimating a design effect or inflation factor. However, where the number of clusters are fixed in advance, but where it is possible(More)
BACKGROUND Much postpartum physical and psychological morbidity is not addressed by present care, which tends to focus on routine examinations. We undertook a cluster randomised controlled trial to assess community postnatal care that has been redesigned to identify and manage individual needs. METHODS We randomly allocated 36 general practice clusters(More)
The history of monitoring the outcomes of health care by external agencies can be traced to ancient times. However, the danger, now as then, is that in the search for improvement, comparative measures of mortality and morbidity are often overinterpreted, resulting in judgments about the underlying quality of care. Such judgments can translate into(More)
By most measures, the adoption of modeling and simulation techniques in healthcare service development falls well short of the uptake of such techniques evident in other sectors, such as business and commerce or aerospace and the military. The question is, why? To answer this, we consider three questions and then turn to the nature of answer which might(More)
Research on surgical interventions is associated with several methodological and practical challenges of which few, if any, apply only to surgery. However, surgical evaluation is especially demanding because many of these challenges coincide. In this report, the second of three on surgical innovation and evaluation, we discuss obstacles related to the study(More)
Improvements in the control of haemorrhage after trauma have resulted in the survival of many people who would otherwise have died from the initial loss of blood. However, the danger is not over once bleeding has been arrested and blood pressure restored. Two-thirds of patients who die following major trauma now do so as a result of causes other than(More)
Surgery and other invasive therapies are complex interventions, the assessment of which is challenged by factors that depend on operator, team, and setting, such as learning curves, quality variations, and perception of equipoise. We propose recommendations for the assessment of surgery based on a five-stage description of the surgical development process.(More)