Assumptions and method
Shortening a non-controlling activity may not shorten the project. Recompute the critical path after each change.
Test a scenario
Use the result in a decision
Check dependencies, duration assumptions and resource availability.
Shortening a non-controlling activity may not shorten the project. Recompute the critical path after each change.
Set a baseline and change one assumption to compare outcomes.
A worked example
Follow the fixed teaching example
- Additional cost = 16,500 − 12,000 = 4,500; reduction = 10 − 7 = 3 days.
- Cost slope = 4,500 ÷ 3 = 1,500 per day. Check whether this activity controls completion before spending.
These illustrative inputs describe a project scenario, not a published benchmark. All monetary inputs use the same currency and price basis.
- Normal duration (days)
- 10
- Crash duration (days)
- 7
- Normal cost
- 12000
- Crash cost
- 16500
- Additional cost per day saved
- 1,500
- Maximum activity reduction
- 3 days
Interpret the output only within the assumptions above. Changing the inputs changes the result; it does not validate the inputs.
Source & credit
Common scheduling practice. The critical-path method is associated with James E. Kelley Jr. and Morgan R. Walker; their 1959 paper is the historical reference.
GAO: Schedule Assessment Guide
This is independently written code and explanation of the underlying method. The linked publication, its diagrams and its trademarks remain its owner’s material; no permission to reuse them is implied.