Effective Project Management: Traditional, Agile, Extreme, Sixth Edition

Resource-Leveling Strategies

You can use one of the following three approaches to level project resources:

• Utilizing available slack
• Shifting the project finish date
• Smoothing

This section describes each of these strategies in more detail.

Utilizing Available Slack

Slack was defined in Chapter 5 as the amount of delay expressed in units of time that could be tolerated in the starting time or completion time of a task without causing a delay in the completion of the project. Recall that slack is the difference between the ES–LF window of a task and its duration. For example, if the ES–LF window is four days and the duration of the task is three days, its slack is 4 – 3, or one day.

Slack can be used to alleviate the over-allocation of resources. With this approach, one or more of the project tasks are postponed to a date that is later than their ES date but no later than their LF date. In other words, the tasks are rescheduled but remain within their ES–LF window.

When you are seeking to level resources, having free slack can come in handy. Free slack, as mentioned in Chapter 5, is the amount of delay that can be tolerated in a task without affecting the ES date of any of its successor tasks. When you need to resolve the “stack-up” of tasks on the schedule, first determine whether any of the tasks has free slack. If any of them do, and if rescheduling the task to that later start date will solve the resource over-allocation problem, you are done. If moving the start date of the ...