Control charts, Cusum techniques and funnel plots. A review of methods for monitoring performance in healthcare.

Quality control in medicine is generating more and more interest. Industrial concepts of quality control have been refined and transformed to be useful in healthcare monitoring. Whereas medical practitioners first reaction to this new concept of quality control was negative 'we're treating patients, we're not a part of an industrial process', some dramatic cases of inferior medical performance urged the need to adequately monitor healthcare outcomes. To date, several methods have been described, and more and more reports deal with the subject. Most of us, however, are overwhelmed by the new and different tools in use such as Shewhart control charts, cumulative sum charts and funnel plots. This paper will review the methodology of statistical process control and its application in medical practice.