Utility of P charts and funnel plots in presentation and analysis of clinical indicator data for a stroke clinical network.

Abstract

Background: Audit and feedback of performance in clinical indicators has been a cornerstone activity of the Queensland Statewide Stroke Clinical Network since 2004. Aim: We demonstrate a useful data presentation format which graphically displays performance within statistical confidence limits. Methods: P charts are used to display performance trends over time and allow recognition of statistically significant temporal trends. Funnel plots are utilized to display individual facility performance against peers. Results: Examples are provided of: p chart demonstrating statistically significant improvements in performance in dysphagia screening correlating with introduction of clinical practice incentive payments; p charts demonstrating significant downward trends in prescription rates of antiplatelet and antihypertensive agents from previously acceptable performance levels (which precipitated network activity to reverse the trends); and funnel plots highlighting significant under-performance of local sites leading to local quality improvement activity. Conclusions: These presentation formats are powerful tools to direct network activity for whole of State issues as well as highlight inter-facility variation for more local quality improvement efforts. The value of practice improvement payments is statistically supported, with future data anticipated to demonstrate the effects of withdrawal of such incentives.<br />