The critical path is the longest sequence of dependent activities that determines project finish date. In a standard CPM baseline, activities on that path typically have zero total float, so delays there delay the project unless scope, resources, or sequence changes.
- Dependency quality matters more than tool choice.
- Critical path can change as progress and estimates change.
- Float is a planning buffer, not free time to ignore.
Build a dependency-first schedule
Start from work packages, then define activity sequence and dependency type. Confirm that predecessor logic reflects real technical and business constraints.
Estimate durations with team input and document assumptions. Unstated assumptions make schedule variance harder to explain.
Use critical path for decisions
Track critical activities weekly. If one slips, decide quickly whether to add capacity, resequence work, or narrow scope.
Monitor near-critical paths too. A path with low float can become critical after one moderate delay.
- Recalculate path after major estimate or dependency changes
- Separate reporting milestones from work activities
- Log approved schedule baseline changes
Critical path for pilot launch
Harbor Health must launch a clinic pilot by October 1.
- Sequence key activities: security review, integration testing, user training, and pilot readiness sign-off.
- Calculate earliest and latest dates and identify zero-float chain.
- Detect delay risk in integration testing and add a second test engineer to protect the date.
- Recalculate schedule and confirm pilot milestone still meets October 1.
Common mistakes
- Treating all tasks as equally schedule-critical.
- Using finish dates without explicit dependency logic.
- Ignoring near-critical paths with very low float.
- Updating percent complete without recalculating remaining duration.
Try one
What happens if a zero-float activity slips by three days?
The project finish date slips by three days unless corrective action changes path timing.
Sources
- Project Management Institute: What is project management?PMI overview of core project management concepts and practices.
- Google Career Certificates: Project ManagementGoogle overview of practical project management workflows and role expectations.