Critical Path Method (CPM)
DE: Methode des kritischen Pfades (CPM)
A technique to determine the longest path and minimum project duration.
Detailed Explanation
CPM calculates early start, early finish, late start, and late finish dates for all activities without considering resource limitations. It determines minimum project duration by identifying the longest network path.
CPM uses a forward pass (early dates) and backward pass (late dates). The difference between late and early start is the float. Activities on the critical path have zero float — any delay extends the project.
Understanding CPM is essential for PMP certification and practice. It helps PMs focus on duration-driving activities, allocate resources strategically, and decide on crashing or fast-tracking.
Key Points
- Calculates early/late start and finish for all activities
- Identifies the longest path = minimum duration
- Forward pass and backward pass through the network
- Critical path activities have zero float
- Does not consider resource constraints
- Foundation for schedule compression decisions
Practical Example
A construction project with 15 activities: CPM reveals the critical path as Site Prep (5d) -> Foundation (10d) -> Framing (15d) -> Roofing (8d) -> Interior (12d) = 50 days. Electrical (7d) runs parallel to framing with 8 days of float.
Tips for Learning and Applying
Identify the critical path before attempting schedule compression
The critical path can shift during execution
Use alongside resource leveling for realistic schedules
Monitor near-critical paths — they can easily become critical
Want to Master These Concepts?
Our courses cover all these terms in depth with practical examples and exercises.