Schedule Compression Techniques Guide: Fast-Tracking vs. Crashing
Why Schedule Compression is Important
Schedule compression is a crucial project management technique that helps teams meet deadlines when facing time constraints. In real projects, delays happen, stakeholders change requirements, or management might decide to accelerate the project timeline. When any of these occur, project managers must know how to compress the schedule while maintaining scope and quality.
What is Schedule Compression?
Schedule compression refers to techniques used to shorten the project duration while maintaining the original project scope. The PMBOK Guide identifies two primary schedule compression techniques:
1. Fast-tracking: Performing activities in parallel that would normally be done in sequence
2. Crashing: Adding more resources to critical path activities to complete them faster
How Schedule Compression Works
Fast-tracking:
- Activities normally done in sequence are overlapped or performed simultaneously
- Example: Starting design of phase 2 before phase 1 design is fully complete
- Requires minimal additional resources
- Increases risk due to dependencies between parallel activities
- Can lead to rework if earlier activities impact later ones
- Does not typically increase direct costs
Crashing:
- Adding resources (people, equipment, overtime) to critical path activities
- Example: Assigning two developers instead of one to code a critical module
- Always increases costs
- Seeks the maximum schedule compression for the minimum cost increase
- May cause diminishing returns (adding more resources doesn't always proportionally speed things up)
- Could create resource conflicts
Key Differences Between Fast-tracking and Crashing:
| Fast-tracking | Crashing |
|---|
| Changes activity relationships | Adds resources |
| Little to no cost increase | Always increases cost |
| Increases risk | May increase coordination complexity |
| Compresses schedule by overlapping activities | Compresses schedule by shortening activities |
Exam Tips: Answering Questions on Schedule Compression Techniques1.
Identify the constraint:
- If time is the constraint but budget is flexible, crashing may be appropriate
- If both time and budget are constraints, fast-tracking might be preferred
2.
Look for keywords:
- "Parallel activities" or "overlapping phases" suggest fast-tracking
- "Additional resources" or "increased cost to accelerate" indicate crashing
3.
Remember the risks:
- Fast-tracking increases quality risks and may require rework
- Crashing increases costs and may face diminishing returns
4.
Critical path focus:
- Only compressing activities on the critical path will reduce project duration
- Compressing non-critical activities just increases their float
5.
Common exam scenarios:
- A project is behind schedule—which technique should be used?
- What are the impacts of using a specific compression technique?
- Which technique increases risk but not cost?
- Which technique should be tried first before increasing project costs?
6.
Watch for hybrid approaches:
- Many real projects use both techniques together
- Determine which is more appropriate based on the specific scenario
In the exam, always consider the project constraints (time, cost, scope, quality) when selecting a schedule compression approach. Remember that fast-tracking increases risks while crashing increases costs.