What are common methods for initial and ongoing project cost estimation?

• A. Elemental/assemblies estimates aligned with design progress and updated with changes
• B. Rough order of magnitude estimates early in the project
• C. Unit cost databases for quick reference
• D. Parameter-based estimates using design progress as input

Answer: (C)

Using unit cost databases as a quick-reference basis for estimating costs is essential for both starting budgets and ongoing cost control. These databases provide standard costs per unit of work (per square foot, per linear foot, per cubic yard, etc.), so you can rapidly turn measured quantities from drawings and specifications into a total estimate. As the design evolves, you can update the unit costs to reflect current market conditions, geography, or project type, and re-run the calculations without rebuilding the entire estimate structure. This approach offers consistency across the team and a straightforward way to track changes in cost as quantities and assumptions shift.

Other methods exist, such as rough order-of-magnitude estimates used early to screen feasibility, or more detailed elemental or parameter-based estimates that align with design progress. These can be valuable for deeper planning or when more detail is available, but they require more development and time and are not as agile for rapid, ongoing updates as unit cost databases.