Exam PK0-004 topic 1 question 757 discussion

This is what I found on the web, and the answer makes sense. The MOST likely reason the project manager was unable to predict the decline in the project metrics, despite reporting all metrics at green status for several months, is that the estimated task durations in the work breakdown structure (WBS) were incorrect. The WBS is a hierarchical decomposition of the project into smaller, more manageable components that can be planned, scheduled, and tracked. The estimated task durations in the WBS are an important input into the project schedule and help the project manager to track progress against the baseline plan. If the estimated task durations in the WBS are incorrect, the project manager may not have an accurate view of the project's progress, which can lead to a failure to predict a decline in metrics.