Fig. 1From: Early recognition and response to increases in surgical site infections using optimized statistical process control charts—the Early 2RIS Trial: a multicenter cluster randomized controlled trial with stepped wedge designExample SPC charts used for SSI surveillance in the Early 2 RIS Trial; Chart A (top) is a moving average (MA) chart using DICON baseline rates and Chart B (bottom) is a moving average (MA) chart using local hospital ratesBack to article page