Mandatory Dependency
A dependency where the sequence of activities is dictated by a contract or by the inherent, built-in logic of the work, leaving no practical alternative order.
Key Points
- Non-negotiable: the order is fixed by contract terms or the nature of the tasks.
- Often modeled as finish-to-start, though any logical relationship can apply.
- Misclassifying it as discretionary can create unrealistic schedules and rework.
- Confirm through contract documents, technical constraints, and compliance needs.
Example
The contract requires customer approval of requirements before design begins, and the structure must be built only after the foundation is poured and cured. Both sequences are mandatory because they are either contractually required or inherent in the work.
PMP Example Question
Which scenario best represents a mandatory dependency?
- The contract requires client sign-off on requirements before design can start.
- The team prefers to finish user documentation before development for clarity.
- Testing is delayed while waiting for a third-party tool license renewal.
- Two activities are sequenced because the same engineer is needed for both.
Correct Answer: A — Mandatory dependency
Explanation: Option A is mandated by contract, fitting a mandatory dependency. B is discretionary, C is an external dependency, and D is a resource-driven constraint.
