Fig. 2
From: Learning curve of laparoscopic Kasai portoenterostomy for biliary atresia: report of 100 cases
CUSUM analysis of operative time (ORT) shows two distinct phases of the learning curve for laparoscopic Kasai portoenterostomy (LKPE). CUSUM of ORT is plotted on the vertical axis against the respective case number. Phase 1 reveals a sharp rise in CUSUM of ORT before the first 20 cases. Phase 2 displays a significant reduction in CUSUM of ORT after case 20, followed by a very slow increase in CUSUM of ORT with stabilization near case 50. Phase 3 indicates a significant reduction in CUSUMORT after case 50