Critical Path

Term Definition
Critical path analysis or critical path method is a project management technique used to predict project duration and, therefore, is useful for both project scheduling and resource planning. The Critical path represents the sequence of tasks or events that directly impact project completing. Project managers can shorten or at the least control a project's schedule by focusing on critical path tasks. This is referred to as critical path management.

Understanding the critical path sequence provides you with information on where you have flexibility and where you do not. On every project there are activities or tasks that have flexibility. The task can start earlier or later without jeopardizing the completion date. The flexibility between the earliest time that an activity can be completed and the latest time that it must be completed is referred to as float. By definition if an activity has float it is not on the critical path.

If your project falls behind schedule you will not want to assign additional resources to non-critical activities, as this will not result in the project completing earlier. Critical path analysis identifies the tasks that are dependent upon one another. When the dependent tasks times are added together, you can predict the longest time necessary to complete the project, which is the critical path. To estimate overall project duration it is important to know the tasks that can happen independently of one another and those that must be done in a certain sequence. Therefore, the critical path is the longest sequence of activities with zero float. If an activity on the critical path is late the entire project will be delayed.

For example, assume that a project is 10 months long. After scheduling the work, you identify the critical path. There are 15 activities in the critical path of various durations and effort hours. The third activity on the critical path was estimated to be completed in five days but actually took nine. The project will now take 10 months and 4 days to complete. Delaying the activity by 4 days caused the entire project deadline to go over by 4 days.

Area of Application
Project Plan

Related Terms
Earned Value
Gantt Chart
Pert Chart
Task Dependency

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