Bid leveling glossary: construction bidding terms, defined

By The GeneralBid team · Last reviewed September 27, 2026

The words estimators, project managers and subcontractors use when a trade package is bid, levelled and awarded, each defined in a few sentences. For the method end to end, read how to level subcontractor bids.

Alternate

Also: alt, add alternate, deduct alternate

A separately priced option the owner may accept or reject, such as a different finish or product. Alternates are compared side by side and kept out of the base totals.

Base bid

The lump sum written on a proposal for the scope as drawn and specified, before alternates. If a proposal gives only line prices, the base bid is their sum.

Bid bond

A surety bond guaranteeing that a bidder will sign the contract at its bid price if awarded. Proposals differ on whether bond cost is included, which is worth levelling like any other line. Bid bond on Wikipedia ↗

Bid leveling

Also: bid levelling, bid tabulation, bid comparison

Adjusting subcontractor bids for one trade so they price the same scope, then comparing them. Each bid is read against one scope list, every excluded or unmentioned line is priced with a plug, and the bids are ranked on the levelled totals. How to level subcontractor bids →

Bid spread

The gap between the lowest and highest levelled bids, as a percentage of the lowest. A wide spread usually means the bidders read the scope differently, and is worth a clarification before award.

Buyout

The period after the GC wins the prime contract when it awards subcontracts and purchase orders for each trade. Bid levelling is the core of buyout.

Certificate of insurance

Also: COI

A document from a sub's insurer showing its policies, limits and expiry dates. GCs collect a current COI before award and before work starts, and track when it expires. Certificate of insurance on Wikipedia ↗

Change order

A written change to a contract's scope, price or time after it is signed. Scope gaps that were not caught at award are among the most common causes. Change order on Wikipedia ↗

Clarification

A written question to a bidder, after bids arrive, asking them to confirm or price specific lines. Answers go back into the levelling sheet before award, so nothing is agreed only on the phone.

Coverage

The share of the base scope lines a bid prices or includes. A bid with low coverage is carrying many plugs, so its levelled total depends heavily on how those plugs are priced.

CSI MasterFormat

The Construction Specifications Institute's standard for organising specifications into numbered divisions, such as 03 for concrete and 09 for finishes. Trade packages and cost codes usually follow it. MasterFormat on Wikipedia ↗

Exclusion

Also: excl., NIC (not in contract), by others

A line a bid explicitly leaves out of its price. Because the sub has said so, you can ask for an add price. In levelling, an exclusion is priced with a plug so the bid covers the full scope.

Form W-9

The US IRS form a subcontractor gives a GC with its legal name and taxpayer identification number, so payments can be reported. About Form W-9 at irs.gov ↗

Hit rate

Also: win rate

For a sub, the share of bids submitted that were awarded. For a GC's directory, it also means how often a sub responds to invitations at all.

Invitation to bid

Also: ITB

The request a GC sends subcontractors to price a trade package, with the scope, documents and due date. Subs who respond submit a proposal.

Levelled total

Also: leveled bid, adjusted bid

A bid's stated number plus its plugs. It is the figure that compares like for like, and the one to rank bids on.

Omission

Also: not mentioned, silent

A line a bid neither prices, includes nor excludes. It is more dangerous than an exclusion because nobody notices it until construction, when it turns into a change order. Levelling prices it with a plug and flags it for clarification.

Plug

Also: plug number

The amount added to a bid for a line it excluded or did not mention, so every bid covers the same scope. Usually your own estimate, the median of the other bidders' prices for that line, or the highest of them. How to price an exclusion →

Prequalification

Checking a subcontractor before inviting them: insurance, licence, bonding capacity, safety record, financials and experience. It keeps bids from subs you could not award to out of the levelling.

Qualifications

Also: clarifications and assumptions

The conditions a sub attaches to a proposal: what it assumes about schedule, access, working hours or other trades. Qualifications can change what a bid covers as much as an exclusion does, so read them before ranking.

Schedule of values

Also: SOV

The breakdown of a subcontract's price into lines, used to bill progress each month. An awarded package's levelled lines are a natural starting point for it.

Scope gap

Work the project needs that a bid does not cover, either because the bid excludes it or because the bid never mentions it. Unpriced scope gaps are the usual source of change orders after award.

Scope sheet

Also: scope checklist, bid form, scope of work

The list of lines every bidder for a trade should price, taken from the spec section, a trade template or the GC's own list. Giving subs one scope sheet to price is the simplest way to get comparable bids. Scope checklists for 16 trades →

Trade package

Also: bid package

The portion of a project bought from one kind of subcontractor, such as drywall or electrical, with its own scope, drawings, due date and bidders. Each package is levelled and awarded separately.