Define deliverables and acceptance criteria clearly in the contract. When issues arise, reference the agreement first, then work together on solutions. Documentation protects both parties.
Strong answers cover: clear contracts with defined deliverables and SLAs, regular performance reviews, building relationships alongside contractual enforcement, addressing issues early and directly, and having contingency plans if a vendor fails. Best candidates discuss the balance between partnership and accountability.
Practical PM skill for projects with external dependencies. Candidates who manage vendors purely through contract enforcement miss the relationship aspect. Those who are too lenient accept poor delivery.