Critical Path Method [CPM]

 This method involves the following steps :

• Calculate the Duration for all activities on the Task Network Diagram.
• Calculate the early start [ES], early finish [EF], late start [LS] and Late Finish [LF] for all activities by using Forward pass and Backward pass techniques.
• Identify the number of paths on the Network Diagram.
• Calculate the total duration of each path.
• Identify the path with the longest duration. This path is called Critical Path.
• The Critical Path Duration will be the MINIMUM Project Duration.
• Calculate Total Float for all activities with the formula [LS-ES] or [LF-EF].
• Total Float is the amount of time an activity can be delayed without delaying the project finish date. The float is also called as Slack.
• Identify Activities on Critical Path. These will have zero float which means they HAVE to start and finish on time.