Final answer:
A performance audit assesses how effectively an agency plans, develops, and implements advertising programs for a client, considering both processes and results.
Step-by-step explanation:
A performance audit focuses on the agency's efforts in planning, developing, and implementing the client's advertising programs and considers the results achieved. This sort of audit evaluates how effectively and efficiently an advertising agency delivers on the agreed-upon objectives within the scope of the client’s needs. It not only scrutinizes the advertising outcomes but also the processes employed and whether they align with the client’s goals, budget, and timelines. Performance audits are an essential aspect of ensuring accountability and efficacy in advertising campaigns.