CAPM Practice: Explain when it is appropriate to use a predictive, plan-based approach

The cost of change follows an exponential curve in predictive projects — it is cheapest at the beginning (during planning) and most expensive at the end. This is why comprehensive upfront planning is a cornerstone of predictive methodology: catching errors in requirements or design before work begins is far less costly than changing direction during execution.

**Why not B:** During monitoring and controlling, work is already underway or complete. Changes at this stage require rework on completed deliverables, which is significantly more expensive than changes made during planning when only documents and plans need updating.

**Why not C:** Project closeout is the most expensive time to change requirements. At this point, deliverables are complete and any changes require reworking finished products, retesting, and potentially re-validating with stakeholders. The cost of change is at its maximum.

**Why not D:** During execution, resources are actively working and deliverables are being produced. Changes at this stage require stopping or redirecting work in progress, potential rework of completed components, and schedule replanning — all more costly than planning-phase changes.