Network Path: The Sequencing Logic for Project Schedule

PMBOK v8 Definition

A network path is a sequence of connected activities with dependencies that represents the logical flow of work within a project schedule. It is the foundational element used to calculate the project's critical path, total float, and schedule duration through forward and backward pass analysis.

Why It Matters for the Exam

Network path concepts appear in 15-20% of schedule management questions on the PMI exam, particularly in calculation-based and interpretation scenarios. Exam questions frequently test your ability to identify the longest network path (critical path), calculate float along different paths, and understand how changes to one path affect overall project duration.

Key Points to Remember (for the exam)

Critical Path Definition: The longest network path through the project, determining the shortest possible project duration. Activities on this path have zero total float.
Total Float Calculation: Total float = Late Start - Early Start (or Late Finish - Early Finish). Float represents how long an activity can be delayed without delaying project completion.
Multiple Critical Paths: A project can have multiple critical paths. When this occurs, the project risk increases because any delay on any critical path directly impacts the project end date.
Near-Critical Paths: Paths with total float less than or equal to a threshold value (often 5% of project duration). These require monitoring because they can become critical if delays occur.
Forward Pass: Calculates Early Start and Early Finish by moving from project start to end, adding durations along each network path.
Backward Pass: Calculates Late Start and Late Finish by moving from project end to start, subtracting durations along each network path.
Common Confusion: Network path is NOT the same as the project schedule. Network paths show logical dependencies and sequencing, while the schedule includes dates, resources, and calendar constraints applied to those paths.

Typical PMI Exam Example

A project has three network paths: A-B-D (15 days), A-C-D (12 days), and A-E-D (10 days). The customer requests a 2-day reduction in project duration. Which path should the project manager analyze first? Answer: Path A-B-D (the critical path at 15 days), as compressing the longest network path is the only way to reduce overall project duration.

PMI Exam Traps

Trap: Assuming the network path with the most activities is the critical path Reality: Critical path is determined by total duration, not activity count. A path with 3 long activities may be longer than a path with 10 short activities.
Trap: Confusing total float with free float Reality: Total float affects project completion date; free float only affects the next activity's early start. Free float is always ≤ total float.
Trap: Thinking critical path activities cannot have float Reality: Critical path activities have zero total float, but they may have free float if their successors have slack.
Trap: Believing the critical path is fixed throughout the project Reality: The critical path can change as work progresses, resources are allocated, or delays occur. It must be recalculated during project execution.

Important PMI Connections

Related Concept	Relationship Type	Exam Attention Point
Critical Path Method (CPM)	Calculation technique for	CPM uses network paths to determine the longest path; tested together in schedule analysis questions
Schedule Compression	Applied to network paths	Crashing and fast-tracking both target critical path activities first; exam tests which technique applies to which scenario
Schedule Baseline	Output from network path analysis	The approved schedule baseline is built from the critical network path; changes to baseline require change control
Project Duration	Determined by network path	Total project duration equals the duration of the longest network path; any delay on this path extends the project

Quick Review Questions

A project has four network paths with durations of 22, 19, 18, and 16 days. What is the total float on the 19-day path?
During forward pass calculation on a network path, Activity X has an Early Start of day 5 and a duration of 3 days. What is Activity X's Early Finish?
If a near-critical network path has total float of 2 days and a critical path activity is delayed by 1 day, what happens to the project duration?
A project manager identifies that two network paths have the same duration. How does this affect project risk assessment?
After completing backward pass analysis, Activity Y shows Late Finish of day 20 and Late Start of day 14. What is the duration of Activity Y?

PMBOK v8 Reference

Section 2.2 - Project Performance Domains (specifically the Planning Performance Domain, which addresses schedule development and network path analysis as part of defining the project's logical sequence of work)