According to the PMBOK® Guide and the Standard for Project Management, the iterative and interactive nature of project management creates a fundamental requirement for Project Integration Management.
Integration Management is unique because it includes the processes and activities to identify, define, combine, unify, and coordinate the various processes and project management activities within the Project Management Process Groups. Because a change in one area (like Scope) almost always affects another (like Schedule or Cost), a dedicated Knowledge Area is required to " glue " these components together.
As per PMI documents, Project Integration Management is required to:
Coordinate all other Knowledge Areas: Ensuring that the various elements of the project are properly coordinated.
Manage Interdependencies: Balancing competing objectives and alternative approaches.
Maintain Consistency: Ensuring that the Project Management Plan is synchronized across all its subsidiary plans and baselines.
The other options are incorrect based on their specific functional focus:
Project Communications Management: Focuses specifically on the timely and appropriate generation, collection, distribution, storage, retrieval, and ultimate disposition of project information.
Project Risk Management: Focuses specifically on conducting risk management planning, identification, analysis, response planning, and controlling risk on a project.
Project Scope Management: Focuses specifically on ensuring that the project includes all the work required, and only the work required, to complete the project successfully.
As per the PMI Lexicon of Project Management Terms, Integration Management is the only Knowledge Area that involves making choices about resource allocation, making trade-offs among competing objectives and alternatives, and managing the interdependencies among the project management knowledge areas.
