AEC definitions
A construction estimate is a priced prediction of what the work will cost, built from quantities, production rates, subcontractor quotes, and allowances for risk. A bid is an estimate the contractor is willing to contract for. The estimate is only as firm as the drawings and specifications it was built from.
Definition
Estimators take off quantities, apply labor and material, collect trade quotes, and add general requirements, insurance, bonds, fee, and contingency appropriate to the stage. A schematic estimate and a bid-day estimate should not be talked about as if they had the same range. The documents, the qualifications, and the date define the number. An estimate is not a schedule of values, though it informs one. It is not a GMP until the contract says so.
In depth
Quantities come from the drawings. Unit costs come from history, vendors, and production. Trade work comes from leveled quotes. Overhead and profit are applied last, in the open, so they are not buried in every unit.
Missing documents become allowances or qualifications. Hiding them inside a single lump makes the number look firmer than it is.
Early estimates should state a class or a percent range. Presenting a schematic total as if it were a bid is how owners set a budget the documents cannot hold. Update the estimate when the design changes, and show the delta.
Contingency belongs in the estimate at a size that matches the unknowns, and it should shrink as the documents mature.
The bid includes the addenda, the leveled scopes, and the exclusions the form allows. After submission, it is either the contract basis or it is not. Post-bid shopping that changes the scope is not 'refining the estimate.'
A number with no backup is a guess. The backup is the takeoff and the quote file.
Owners use it to set budget and to choose design options. Contractors use it to bid and to buy out. Lenders use it to size a loan.
Each audience needs the qualifications. A single total with no scope statement serves none of them.
Examples
A CD estimate lists direct costs by trade, general requirements, bonds, fee, and a stated contingency. The drawings and addenda are dated on the cover.
A schematic estimate is labeled with a wide range. The owner does not treat it as a bid.
Bid-day leveling changes which mechanical number is carried. The estimate backup shows the plug and the quotes.
Tooling
Nomic can cite the drawing and specification sections an estimate qualification depends on, so the scope behind the number is visible.
It does not produce a bid or certify a price. The estimator does.
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