Every number should have a source

Ask where a number in last month's bid came from, and watch the folder hunt begin. Most estimates are archaeology: layers of copied cells, "typical" values inherited from older jobs, and dimensions someone once measured off a printout at the wrong scale.

The two kinds of numbers

Every number in an estimate is one of two things. It's extracted — it exists in the tender documents, and you can point to it. Or it's asserted — someone supplied it from experience, assumption, or hope. Both are legitimate tools. The damage happens when asserted numbers dress up as extracted ones, because nobody re-checks a number that looks official.

What a real audit trail looks like

Here's a real example, anonymized, from a residential package we processed. The drawings and specifications stated the bathroom mirror's height — it's in the spec section, traceable. The mirror's width appears nowhere: not on the plans, not in a schedule, not in the spec. The tempting move is to write in a standard width and keep going; every estimator has done it. The honest move is to say: this dimension is not in the documents.

That honest move is what an audit trail looks like in practice. In a CAIRO takeoff, the barn door's width reads 1015 mm ← A-402 — a claim with a source you can flip to. And the mirror's width reads awaiting input, in gold, because the alternative is a fabricated number hiding inside your total. The gap is information: your estimator knows exactly what to verify before quoting, instead of trusting a guess they don't know they made.

We think this should be the norm for the whole industry, which is why it's the rule our product is built on: extraction records what the documents say; everything else is declared, never disguised.