MC9902C02 Chapter Notes - Chapter 1-6: Critical Path Method, Gantt Chart
Critical Path Method
The Critical Path Method or CPM is a network analysis technique concerned with
planning and controlling of complex, but routine projects. Simply, Critical path
method is generally used for the projects whose time duration is known with
certainty and also the number of resources required for the completion of the
project is assumed to be known.
The Critical Path Method is crucial to implement within your construction
business, and can also protect your business from litigation in the instance of
construction disputes. As for construction management, you need to develop a
strong grasp of the CPM and learn the basic techniques required to successfully
implement a Critical Path Method that your business can benefit from.
First of all, the activities comprised in a project are identified along with their
importance, i.e., the dependency of activities on each other. For each activity, it is
identified that which other activities are required to be completed before it starts
and how long the activities take to get finished.
Once the critical activities are identified, the network is drawn connecting all the
crucial activities and depicting which activity to be carried first, so that successor
activities could be performed effectively. For each activity the following parameters
need to be determined:
• Earliest start time (ES): How early, the successor activity begins once the
predecessor activity finishes.
• Earliest Finish Time (EF): Earliest Start Time + duration of each activity.
• Latest Finish Time (LF): The latest time within which the activity finishes
without delaying the project.
• Latest Start Time (LS): Latest Finish Time – Activity duration
The critical path method follows the “activity-on-arc” diagram to illustrate a critical
path of activities (as shown below). This diagram comprises of a numbered nodes
that represent the stages required for the project completion while the arc shows
the crucial activities as identified earlier
