Supplier quote comparison: the mistakes that make the cheapest quote expensive

Every estimator has seen it: three quotes for the same package, the lowest one gets carried, and weeks later it turns out the low number excluded something the others included. The price was never like for like. Industry guides call the fix bid leveling for subcontract packages and quote comparison or normalisation for materials, and the advice behind both is very similar.

The mistakes that keep repeating

• Comparing totals instead of scope. One quote is supply only, another is supply and install. One includes haulage, testing or temporary works; another is silent on it.
• Missing exclusions and qualifications buried in a cover letter or the last page of the PDF.
• Ignoring validity. A quote that expires before award, or that is tied to a metal or fuel price, is not the same offer as a fixed price.
• Mixing units and pack sizes, so a rate per length is compared with a rate per metre.
• Treating an alternative brand or specification as equal without checking it against the specification.
• Not adding delivery terms, lead times and payment terms to the comparison at all.

Estimating coach Tim Fairley lists subcontractor pricing errors among his five worst estimating mistakes, tracing many of them to rushed tenders where the scope sent out was unclear and the quotes coming back were thin. In other words, many comparison problems start with the enquiry, not the comparison.

Practices that fix it

Guides from Archdesk and Beck Technology describe a similar process. In summary:

• Send a structured enquiry. A clear scope, your BOQ lines and a pricing schedule suppliers must fill in make quotes far easier to compare.
• Go line by line. Compare each quote against your scope, not only against the other quotes.
• Keep an exclusions log per supplier, so nothing stays hidden in the PDF.
• Use plug numbers. When a quote excludes something, add an allowance so every bid is compared on the same scope, and record why.
• Normalise units, specification and delivery before comparing price.
• Record validity dates and chase renewals before submission, not after award.

CostCrunch makes a useful distinction: leveling subcontract bids is mostly judgement about scope boundaries, while comparing material quotes is mostly normalising item codes, units and landed cost. Most contractors do both, sometimes on the same tender, and it helps to know which one you are doing.

What a usable comparison looks like

One sheet per package: your BOQ lines down the side, suppliers across the top, normalised rates in the cells, and below them the exclusions, plug numbers, validity date, lead time and payment terms for each supplier. The recommendation is the estimator’s, written next to the numbers, so whoever approves the award can see both the price and the reasoning.

How we approach it

We build quote comparison around your own BOQ lines and enquiry format: quotes are read into one structure with every exclusion and validity date linked to the source PDF, and the carry decision stays with your estimator.