Monitoring postoperative pulmonary embolisms in Australia--II. Variation within hospitals.

Clinical indicator data can be analysed quickly and efficiently within hospitals to provide quality review staff with monthly or quarterly reports on their own hospital's performance relative to national or regional normative statistics. The statistical tools used are indirect standardisation to correct for casemix differences between institutions and control charts, and cumulative sum charts for the analysis and presentation of findings. Routinely collected postoperative pulmonary embolism data are used to illustrate these approaches.