Project’s Critical Path

When a project is underway, there are some activities that affect the project’s ability to move forward. Those
critical activities need to be completed or the project stalls. The project manager needs to look carefully at each
of the tasks in a project and compute the earliest start (ES) and earliest finish (EF) and also the latest start (LS)
and the latest finish (LF) time for each task.
Here is a simplified example: to paint a room, the person doing the taping of the edges plans to start at 7 AM
(ES) and he will be done about 8:30 (EF). Since the painting contractor starts work at 9, the latest taper can
begin is 7:30 (LS) or he will not be done (LF) when the painter plans to begin. These two tasks also have 30
minutes of slack (where the taper can take longer or the painter can come earlier). As part of controlling time
and expenses, it is important for a project manager to know what asks are critical and where there is available
slack when needed.

Sample Solution