What estimating technique aggregates costs from the highest level of the project down to key deliverables?

Top-Down estimating is a technique that involves aggregating costs from the highest level of the project, such as the entire project budget or a program, and then distributing that total down to specific deliverables or project components. This approach allows project managers to quickly estimate costs using historical data or expert judgment without delving into the detailed elements of each deliverable.

This method is particularly useful in the early stages of a project when detailed information may not yet be available. By starting with a broad overview and then narrowing down to specifics, it helps ensure that estimates align with the overall goals and constraints of the project. This can facilitate quicker decision-making and help keep project planning on track.

In contrast, other estimating techniques such as Bottom-Up estimating involve starting at the detailed level of individual tasks or components and aggregating those costs to develop a total project cost, which is a more labor-intensive process. Three-Point estimating relies on a statistical approach, considering optimistic, pessimistic, and most likely estimates, which adds complexity. Parametric model estimating uses statistical relationships based on historical data to compute costs, which might not provide the holistic view needed in the initial phases of a project. Therefore, Top-Down estimating is particularly effective for initial project assessment to establish a budget