Schedule Compression: Shortening Duration Without Reducing Scope

PMBOK v8 Definition

Schedule compression is a technique used to shorten the schedule duration without reducing the project scope. Schedule compression techniques are used to meet schedule constraints, imposed dates, or other schedule objectives. A helpful technique is the negative float analysis. The critical path is the one with the least float. Due to violating a constraint or imposed date, the total float can become negative.

Why It Matters for the Exam

Schedule compression appears frequently in PMI exam questions because it directly tests your ability to manage schedule constraints without scope reduction. You will encounter it in situational questions where the project is behind schedule, has an imposed deadline, or shows negative float on the critical path. Expect questions that ask you to choose between crashing and fast tracking based on cost, risk, and resource considerations.

Key Points to Remember (for the exam)

• Definition: Schedule compression shortens project duration WITHOUT reducing scope
• Trigger Condition: Used when negative float exists on the critical path
• Critical Path Rule: Both techniques work ONLY on critical path activities
• Two Techniques:
  • Crashing: Adds resources to shorten duration for the least incremental cost (examples: overtime, additional resources, expedited delivery)
  • Fast Tracking: Performs activities in parallel that were normally done in sequence (example: starting foundation before completing architectural drawings)
• Crashing Limitations: Does not always produce viable alternatives; may increase risk AND cost
• Fast Tracking Limitations: May result in rework and increased risk; only works when activities can be overlapped
• Primary Difference: Crashing = add resources (higher cost); Fast tracking = parallel work (higher risk)

Typical PMI Exam Example

A project manager discovers the critical path shows -5 days of float because the client imposed an earlier completion date. The project cannot reduce scope. The sponsor approves additional budget. What should the project manager use? Answer: Crashing, because additional resources are authorized and the constraint is cost-based.

PMI Exam Traps

• Trap: Confusing crashing with fast tracking Reality: Crashing adds resources (cost focus); fast tracking overlaps activities (risk focus)

• Trap: Applying schedule compression to non-critical path activities Reality: Both techniques only work on critical path activities where shortening will reduce total project duration

• Trap: Assuming crashing always reduces duration Reality: Crashing does not always produce a viable alternative; adding resources may not shorten duration if the activity cannot be parallelized

• Trap: Thinking fast tracking has no cost impact Reality: Fast tracking may result in rework, which increases cost and risk, even though no additional resources are added initially

Important PMI Connections

Quick Review Questions

1. What is the primary difference between crashing and fast tracking in terms of what they impact most?

2. A project has negative float on the critical path. The sponsor says no additional budget is available. Which schedule compression technique should be considered?

3. True or False: Fast tracking can be applied to any activities in the project schedule.

4. What is the relationship between schedule compression and project scope?

5. When crashing, what must be verified before adding resources to an activity?

PMBOK v8 Reference

Section 5.5 – Develop Schedule (Schedule Compression techniques including Crashing and Fast Tracking)