d. Start to finish d. Start to finish
l-ST ■ 3 LFT - 8 Figure 8-24: Precedence diagramming e. Nomenclature conventions.
known whether each activity can be split or not. Splitting allows easier satisfaction of the lead and lag restrictions. If splitting is not allowed, the project may be significantly delayed.
Some anomalies tend to occur in precedence diagramming that are not encountered in PERT/CPM, For example, because of the lead and lag requirements, activities may appear to have slack when they really do not. Also, the critical path of the network will frequently go backward through an activity, with the result that increasing the activity time may actually decrease the project completion time. Such an activity is called reverse critical. This happens when the critical path enters the completion of an activity through a finish constraint (Figure 8-246 or d), continues backward through the activity, and leaves through a start constraint (Figure 8-24a ord).
Network node times are calculated in a manner similar to PERT/CPM times. Because of the lead and lag restrictions, it is often helpful to lay out a Gantt chart to see what is actually happening.
Precedence diagramming seems to be gaining in popularity. The richer set of precedence relationships it allows is pertinent for a variety of projects, particularly construction projects. For more details on this technique, see [1.12 (Chapters 6 and 17), and 37). Most current project management software will allow leads, lags, delays, and other constraints in the context of their standard AON network and Gantt chart programs.
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What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.