The primary purpose of a post-implementation audit or post-implementation review is to determine whether the system implementation achieved what it was supposed to achieve. In CISA terms, this means confirming whether the project deliverables, controls, and requirements were met. ISACA’s CISA exam content explicitly states that a post-implementation review is conducted to determine whether project deliverables, controls, and requirements are met, which directly aligns with option B.

Option A (“Address lessons learned from the project”) is important, but it is secondary, not the most important objective. ISACA material recognizes that lessons learned may be documented as part of a post-implementation review, but this is presented as a useful activity, not the core audit objective. The central audit question remains whether the implementation delivered what was required.

Option C (“Develop a process for continuous improvement”) is also valuable, but that is a broader management and quality-improvement outcome. It is not the main objective of a post-implementation audit. An auditor’s primary focus is assessment and verification, not designing the organization’s continuous improvement process. ISACA’s audit guidance emphasizes that audit objectives are commonly phrased as determining whether something is adequate or achieved, which supports the selection of option B over improvement-oriented options.

Option D (“Seek approval for the next implementation phase”) is not an audit objective. Approval for the next phase is a project governance or management decision, while the audit function is concerned with whether implemented controls, requirements, and deliverables were achieved.

So, the best answer is B, because ISACA ties post-implementation review directly to confirming that the implementation met its required objectives, deliverables, controls, and requirements.

References (Official ISACA):

ISACA, CISA Exam Content Outline — “Conduct post-implementation reviews of systems to determine whether project deliverables, controls, and requirements are met.”

ISACA, Certification Exam Candidate Guide — same task statement for post-implementation reviews.

ISACA, CISA Certification Application / Task Statements — confirms the same post-implementation review objective.

ISACA Journal, Plan for Successful System Implementations — notes lessons learned may be documented as part of post-implementation review, supporting why this is important but not primary.

ISACA Journal, IS Audit Basics: The Components of the IT Audit Report — supports how audit objectives are framed as determining whether requirements/objectives are met.