According to the PMBOK® Guide and the Standard for Project Management, the ability to influence the final characteristics of the project ' s product and the final cost of the project is highest at the Early stages of the project life cycle.
As per PMI standards, this concept is represented by the relationship between influence, cost, and time. In the initial phases (Initiating and Planning):
High Influence: Stakeholders have the greatest opportunity to influence the project scope and cost because fewer definitive decisions have been made and very little capital has been committed.
Low Cost of Changes: Changing a requirement or design early on (on paper) is relatively inexpensive compared to making the same change later.
Inverse Relationship: As the project progresses toward the Middle and Late stages, the cost of changes increases significantly because work has already been performed, resources have been spent, and materials have been procured. Conversely, the ability to influence the project decreases as more of the project is " locked in. "
The other options are incorrect based on the following PMI project life cycle characteristics:
Middle: During the executing phase, the ability to influence cost begins to drop sharply as the project team focuses on following the approved plan. The cost of changes begins to rise as rework becomes necessary.
Late: By the monitoring and controlling phase (approaching the end), most of the budget has been spent or committed. Influence is very low at this point.
Completion: At the closing phase, the project is finalized. The ability to influence cost is essentially zero because the deliverables are being handed over.
As per the PMI Lexicon of Project Management Terms, front-loading the effort into the early stages of a project allows for better cost management and minimizes the risk of expensive changes during later phases.
