What is the difference between crashing and fast tracking?

Crashing adds extra resources to critical path activities to shorten the schedule, increasing cost but maintaining the original sequence. Fast tracking performs activities in parallel that were originally planned in sequence, increasing risk but not necessarily cost.

When should you use crashing vs fast tracking?

Use crashing when the schedule must be shortened and additional budget is available, and activities can be accelerated with more resources. Use fast tracking when activities have some overlap potential and you want to compress the schedule without adding cost, but can accept increased risk.

What are the risks of fast tracking a project?

Fast tracking increases the risk of rework because parallel activities may produce conflicting results. It can lead to quality issues, communication problems, and additional costs from rework if the overlapped activities produce outputs that need revision.

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Study Notes

Schedule

Crashing vs Fast Tracking — Schedule Compression for PMP

Key differences between crashing and fast tracking schedule compression techniques in project management. Includes when to use each, risks, and PMP exam tips.

Overview

Both crashing and fast-tracking are schedule compression techniques.
Both techniques aim to compress the project schedule without compromising on the scope.

Crashing

Crashing is a schedule compression technique that involves determining an approach that brings maximum reduction in project duration with least incremental cost and risk, and without changing the scope.

In Crashing, project schedule is compressed by adding more resources to the project, or working overtime to the critical path activities. The key here is "critical path activities". If you apply additional resources to non-critical path activities, it would not result in a compressed schedule.

Drawbacks of Crashing

Increased Risks
Increased Costs
May not always result in a compressed schedule

Fast Tracking

Fast tracking is a schedule compression technique that reduces the project duration by performing critical path activities in parallel that were originally planned to be performed in sequence.

in Fast Tracking, activities which are usually performed in sequence are performed in parallel, to compress the schedule.

As with Crashing, the goal of Fast Tracking is to shorten the duration of the critical path. Therefore, Fast Tracking only works when activities can be overlapped to shorten the critical path duration.

Drawbacks of Fast Tracking

Increased Risks (especially quality risks)
Rework
May also increase project costs

Differences between Crashing and Fast Tracking

In Crashing, schedule is compressed by applying additional resources, working overtime, etc. to critical path activities, whereas in Fast Tracking, activities which are usually performed in sequence are performed in parallel, to compress the schedule.

Crashing vs Fast Tracking Schedule Compression Techniques

In the diagram above, the normal case represents a project with 3 phases, and a duration of 12 weeks with one resource assigned throughout.

With Fast Tracking, some parts of the projects are performed in parallel resulting in a schedule compression by 3 weeks, with one resource assigned throughout. Phase 2 overlaps with phase 1 in weeks 3 and 4, and phase 3 overlaps with phase 2 in week 6.

With Crashing, additional resources are added to the project to compress the schedule by 4 weeks, while performing the phases in sequence. Phase 1 and Phase 2 have two resources assigned, while phase 3 has three resources assigned.

Note that the above example does not imply that Crashing is more effective than Fast Tracking, or the other way around.