Contractor Quote Duel

Three quotes for "the same" roof project are rarely the same project. One bids 1,900 sq ft of shingles and nothing else; one includes gutters and skylight flashing; one is $4k cheaper because tear-off disposal is a change order waiting to happen. Homeowners compare totals — the single most misleading number in the stack — because building a scope matrix by hand across PDFs is tedious. This skill does the comparison mechanics: scope union, gap exposure, unit-price outliers, payment risk, and the clarification emails that turn apples/oranges into a decision.

When to Use

• 2-4 written quotes in hand for the same project, deciding who gets it
• One bid dramatically cheaper — is it efficient or incomplete?
• Deciding what to ask each bidder before signing anything
• Checking a quote's payment structure before handing over a deposit
• Change-order dispute later: was the item in the original scope?

Don't use for: new construction custom builds (different economics — cost-plus vs fixed-price needs a contract review, not a comparison matrix); storm-chaser door-knockers (walk away, don't analyze); anything needing a structural engineer's stamp (get the engineer).

The Method

1. Extract quotes to JSON (agent does this from PDFs/photos/text): bidder, total, deposit %, items (name/price/qty), docs promised, licensed/insured flags.
2. matrix — scope union × bidder grid; every "— MISSING" cell is a scope gap you'd discover as a change order. Plus documentation completeness per trade (roof quotes without ice/water shield specs, kitchens without permit responsibility, HVAC without load calc).
3. pricecheck — unit price = price/qty vs ballpark band per trade.

   1.6× band high = padding; < 0.5× band low = lowball — the classic change-order bait.

4. risk — deposit & payment-schedule exposure. Deposit >30%, nothing written, >60% due before completion, uninsured: LOW/MEDIUM/HIGH.
5. letter — scope-gap clarification email per bidder listing exactly what competitors included that they didn't, plus the four questions (payment schedule, timeline, permits, labor warranty).

Q='[{"bidder":"Alpha Roofing","total":9500,"deposit_pct":10,"insured":true,
"items":[{"item":"asphalt roof replacement","price":9500,"qty":1900}],
"docs":["tear-off layers and disposal included"]},
{"bidder":"Beta Exteriors","total":14200,"deposit_pct":50,"insured":false,
"items":[{"item":"asphalt roof replacement","price":11800,"qty":1900},
{"item":"gutter replace","price":1200,"qty":80}],"docs":[]}]'

python3 scripts/quote_duel.py --quotes-json "$Q" matrix
python3 scripts/quote_duel.py --quotes-json "$Q" pricecheck
python3 scripts/quote_duel.py --quotes-json "$Q" risk
python3 scripts/quote_duel.py --quotes-json "$Q" letter --bidder "Alpha Roofing" --project "roof replacement"

Decision Rules (from the outputs)

• Never decide on totals: decide on normalized scope + unit prices.
• A bid missing >30% of the union scope isn't cheaper — it's undefined. Get the gaps priced before comparing.
• Deposit >30% or >60% pre-completion is walk-risk; many US states cap deposits at 10-30% by trade.
• Cheapest bid + LOW unit-price flags = change-order farm. Budget total × 1.25 as the realistic number.
• Insurance/license unverified = stop. Verify before any money moves.

Common Pitfalls

1. Comparing totals across different scopes. The matrix exists precisely because totals lie. Every MISSING cell must be priced or excluded in writing before a decision.
2. Forgetting qty. Unit-price checks need quantity (sq ft, linear ft, windows). A $9,500 roof bid without area can't be sanity-checked — ask for measurements.
3. Trusting allowances. "Allowance $1,500 for fixtures" is not a price. Convert allowances to spec-or-unit-price in the clarification letter.
4. Ballpark bands as gospel. Bands are US national order-of-magnitude; regional spread is 2×. Use flags to ask questions, not to accuse.
5. Ignoring documentation gaps. The docs checklist per trade is the cheapest dispute insurance: no ice/water shield spec on a roof quote is how you get felt-only under a $12k roof.
6. Paying to a point of no leverage. Final payment after punch list, always. A contractor with 100% of the money has zero incentive to return.
7. Verbal "yes that's included." If it isn't a line item after the clarification letter, it doesn't exist.

Verification Checklist

• Every scope item in the union appears in the final contract of the winner (line items, not summaries)
• Unit-price outliers resolved in writing (spec'd or re-priced)
• Deposit <=30%, schedule written, final payment after punch list
• License + insurance verified with the state/insurer directly
• Permit responsibility named in the contract
• Change-order rule written: signed + priced before extra work

References

• references/trade-scope-checklists.md — what a complete quote must contain per trade (roof/kitchen/bath/HVAC/electrical/structural), allowance traps, contract clauses that survive disputes, and the lowball-bid pattern catalog.