Network Logic refers to the set of dependencies and relationships that connect all scheduled activities within a project schedule network diagram. It defines the sequence in which tasks must be executed, based on constraints, resource availability, and logical order. The structure created by network logic forms the foundation for critical path analysis, float calculation, and scheduling decisions.
Purpose and Characteristics
- Defines Activity Sequencing – Establishes which tasks must occur before, after, or concurrently with others.
- Enables Schedule Calculations – Used to compute early/late start and finish dates.
- Built on Logical Relationships – Includes finish-to-start, start-to-start, finish-to-finish, and start-to-finish dependencies.
- Essential for Path Analysis – Supports identification of critical and near-critical paths.
Example Scenario
In a software project, coding must finish before testing begins. This finish-to-start dependency is part of the network logic. If documentation can start while testing begins, a start-to-start relationship is also included—adding complexity to the network logic.
Mermaid Diagram: Sample Network Logic with Dependencies
flowchart LR A[Requirements] -->|Finish-to-Start| B[Design] B -->|Finish-to-Start| C[Development] C -->|Start-to-Start| D[Documentation] C -->|Finish-to-Start| E[Testing] E -->|Finish-to-Start| F[Deployment]
This diagram demonstrates how logical relationships define the order and constraints between project tasks.
Why Network Logic Matters
- Prevents Scheduling Conflicts – Ensures the sequence respects technical and practical constraints.
- Drives Accurate Forecasting – Forms the basis for start/finish date calculation and float determination.
- Enables Critical Path Identification – Helps project managers prioritize tasks that directly affect project duration.
See also: Network Path, Early Start Date, Early Finish Date, Late Start Date, Late Finish Date, Logical Relationship.