Critical Path

The Critical Path is the sequence of activities that represents the longest path through a project, determining the shortest possible duration for project completion. Any delay in a critical path activity directly impacts the project’s finish date.

Key Aspects of the Critical Path

• Determines Project Duration – Defines the minimum time needed to complete the project.
• Identifies Critical Activities – Tasks on the critical path cannot be delayed without extending the project timeline.
• Has Zero Float (Slack) – Critical tasks have no scheduling flexibility.
• Used in the Critical Path Method (CPM) – Helps in scheduling, resource allocation, and risk management.

Example Calculation of Critical Path

Activity	Duration (Days)	Predecessor
A	3	Start
B	5	A
C	2	A
D	4	B
E	6	C
F	3	D, E
G (End)	2	F

Critical Path Determination

1. Identify all paths through the project network.

   • Path 1: A → B → D → F → G → (Total: 3+5+4+3+2 = 17 days)
   • Path 2: A → C → E → F → G → (Total: 3+2+6+3+2 = 16 days)

2. Select the longest path.

   • Critical Path: A → B → D → F → G (17 days)

Mermaid Diagram: Critical Path Example

graph LR;
    Start["Project Start"] --> A["Task A (3d)"]
    A --> B["Task B (5d)"]
    A --> C["Task C (2d)"]
    B --> D["Task D (4d)"]
    C --> E["Task E (6d)"]
    D --> F["Task F (3d)"]
    E --> F
    F --> G["Task G (2d)"]
    G --> End["Project Completion"]
    class A,B,D,F,G critical;

Why the Critical Path Matters

• Defines the Minimum Project Duration – Helps set realistic completion deadlines.
• Highlights High-Risk Activities – Delays in critical path tasks directly impact the schedule.
• Aids in Resource Allocation – Focuses attention on critical activities requiring priority resources.
• Enables Proactive Schedule Management – Allows project teams to anticipate and mitigate potential delays.

See also: Critical Path Activity, Critical Path Method (CPM), Schedule Network Diagram, Total Float.