Crashing
Crashing is a schedule compression technique in which additional resources are added to critical path activities to reduce their duration at the least additional cost.
Explanation
Crashing is one of two primary schedule compression techniques. It involves adding resources to activities on the critical path to reduce the project duration. Typical crashing strategies include assigning additional team members to an activity, authorizing overtime, paying for expedited delivery of materials, or using more experienced (and more expensive) resources.
The key principle of crashing is to achieve the maximum schedule compression for the minimum incremental cost. To do this, the project manager analyzes the critical path activities, determines the crash cost per unit of time saved for each activity, and then crashes the activities in order of lowest cost per unit of time saved. Crashing continues until the desired schedule reduction is achieved, no more crashing is possible, or the cost of further crashing exceeds the benefit.
Crashing does not always work. Some activities cannot be shortened by adding resources due to the nature of the work (for example, a task that requires sequential drying or curing time). Adding too many resources can also create diminishing returns or negative effects due to coordination overhead. Crashing always increases cost and may also introduce additional risk.
Key Points
- •Adds resources to critical path activities to reduce duration
- •Always increases project cost
- •Applied to activities with the lowest crash cost per time unit saved first
- •Not all activities can be effectively crashed
Exam Tip
On the exam, crash the critical path activity with the lowest crash cost per unit of time saved first. If the critical path changes after crashing, recalculate.
Frequently Asked Questions
Related Topics
Schedule Compression
Schedule compression is a technique used to shorten or accelerate the project schedule duration without reducing the project scope.
Fast Tracking
Fast tracking is a schedule compression technique in which activities or phases normally done in sequence are performed in parallel for at least a portion of their duration.
Critical Path
The critical path is the longest sequence of activities in a project schedule network diagram that determines the shortest possible project duration.
Develop Schedule
Develop Schedule is the process of analyzing activity sequences, durations, resource requirements, and schedule constraints to create the project schedule model for project execution, monitoring, and controlling.
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