Duplicate Relationships

A duplicate relationship occurs when you link the same two activities with more than one relationship type (for example, both Finish-to-Start and Start-to-Start) in a CPM schedule. Instead of one clear dependency, you have two competing ties between the same tasks. This can cause several issues, such as:

• Creates ambiguity: It becomes unclear which dependency is “real” or relevant.
• Resource inefficiencies: Team members may get mixed priority signals.
• Reduced accountability: Harder to determine which dependency is binding, and who is responsible.
• Schedule inaccuracies: The critical path and logical flow can be distorted.
• Error-prone updates: Changes may break or conflict with duplicate ties.
• Analysis difficulty: Makes tasks like delay impact, constraint tracing, and performance measurement more complicated.

Always aim for each dependency between two activities to be represented by just one properly defined relationship that reflects the actual dependency.