Page 290 - The Handbook for Quality Management a Complete Guide to Operational Excellence

276 C o n t i n u o u s I m p r o v e m e n t D e f i n e S t a g e 277

Immediately Earliest Time + Maximum = Earliest
Event Preceding Event Activity Time Completion Time
1 — — 0
2 1 0 + 2 2
3 2 2 + 4 6
4 3 6 + 10 16
5 4 16 + 4 20
6 4 16 + 6 22
7 4 16 + 7 *
5 20 + 5 25
8 5 20 + 0 *
6 22 + 7 29
9 7 25 + 8 33
10 8 29 + 9 38
11 9 33 + 4 37
12 9 33 + 5 38
11 37 + 0 *
13 10 38 + 2 *
12 38 + 6 44

Table 13.3 Calculation of Earliest Completion Times for House Construction Example

estimated latest time the event can occur without delaying the comple­
tion of the project beyond its earliest time. Earliest times of events are
found by starting at the initial event and working forward, successively
calculating the time at which each event will occur if each immediately
preceding event occurs at its earliest time and each intervening activity
uses only its estimated time. Table 13.3 shows the process of finding the
earliest completion time for the house construction example. (Event
numbers refer to the network diagram in Fig. 13.7.) The reader is advised
to work through the results in Table 13.3, line­by­line, using Fig. 13.7.
Thus, for example, the earliest time event #8 can be completed is
29 days. (Note that the asterisks in Table 13.3 denote calculations that
resulted in the non­maximum condition. For example, event #8 occurs
when both events #5 and #6 have been completed, so the maximum time
calculation is used).
Latest times are found by starting at the final event and working back­
ward, calculating the latest time an event will occur if each immediately
following event occurs at its latest time. Table 13.4 displays the calculated
latest completion times for the house construction example.

13_Pyzdek_Ch13_p265-292.indd 277 11/9/12 5:14 PM