Both Critical Path Method (CPM) and
Precedence Network Analysis (PNA) belong to family of network analysis
techniques.
- Make use of the network-type
graphic model to depict the time plan for execution of the project.
- Apply the critical path
analysis concept for determining project duration and identifying critical
activities.
- Employ these network analysis
techniques for scheduling and controlling of projects.
Although CPM and PNA network models
may appear different, logically they are similar. For a given project, both CPM
and PNA network contain same job activities and durations. In case of networks
using finish-to-start logic, even activity times and extent of floats are
equal.
Generally, a CPM network can be
converted into a PNA network by the following steps:
- Delete dummy activities and
isolated start and end events.
- Identify preceding events of
all the non-dummy activities.
- Draw boxes around the non-dummy
activities to enclose the preceding event, activity description and its
duration.
- Develop PN by linking activity
boxes with dependency lines using the finish-to-start relationship.
To quote another
example, the PN of the factory project thus developed, along with its CPM
network for comparison. Note that PNs having multiple logic constraints cannot
be converted into CPM networks without further splitting the affected activities.
Both PNA and CPM are
used extensively for planning construction projects. They have some common
features as well as significant differences.