The build-up diagram is used below to analyze the backlog of patients in the waiting room before visiting RNs. Number of F B 7 6 Build-up Diagram 62 74 = 2 1 0 De 7 8 9 10 11 12 13 14 15 10 17 Time Average number of Patients at RN Step Time Hours Start pts End pts Avg pts 7 to 12 S 0 5 2.5 Time 7 to 12 Average flow rate Pts/hour Hours 7 5 12 to 14 2 S 7.4 6.2 12 to 14 2.8 2 14 to 15 1 7.4 8.4 7.9 14 to 16:12 7 2.2 15 to 16:12 12 8.4 0 4.2 Grand Weighted Mean 4.11 Weighted Average 6.09 pts/hr