The use of databases to identify both good and bad (acceptable and unacceptable) trends in the performance of simple and complex procedures in medicine has a long history and was advocated by such important medical and nursing practitioners as Florence Nightingale, Ernest Codman, Lord Moynihan and others [1–7]. Unfortunately, not all of these committed clinicians have gained the respect of their local medical colleagues [2,8,9]. Thus the need for objectively endorsed systems to monitor the occurrence of adverse clinical outcomes in day-to-day practice is paramount [10–12]. In pursuit of this goal the article by Spiegelhalter et al. in this issue is a welcome contribution [13]. The demonstration by the authors that the adverse events occurring in the practice of both the paediatric cardiac surgeons in Bristol and the general practitioner Harold Shipman could have been detected by routine data monitoring confirms earlier work arising from the Kennedy Inquiry and the Dame Janet Smith Inquiry [14–16]. Unfortunately, in the Bristol case, similar information had already been presented to the surgeons, anaesthetists and managers involved in the care of these patients with little impact on the service [17,18]. In fact a Cusum graph based on the same criteria employed by the Great Ormond Street paediatric cardiac surgery group had …