The first page of an estimate often tells a reviewer who prepared it and how much the project might cost. The explanation of why it costs that amount can be much harder to find.
A basis of estimate earns its place when it answers the questions that the workbook cannot answer on its own. What information was available? Which revision was measured? What does the price assume about access and working hours? Which decisions remain with the client?
AACE’s Recommended Practice 34R-05 addresses the basis of estimate. For a working team, a practical implementation is to make the basis part of the estimating process from the beginning, rather than writing an account of it after the total has been agreed.
- Defined scope
- Measured quantity
- Resource and output basis
- Price source and date
- Review record
An original review sequence. It is not a reproduction of an AACE template.
Start with the assumptions that could move the price
Consider a concrete package with restricted deliveries. A supplier’s rate may look competitive, but the work could require smaller loads, more bookings and a different pumping arrangement. The estimate should identify those conditions beside the relevant allowance.
Give each unresolved assumption an owner and a review date. “Access to be confirmed” records a problem without providing a way to close it. “Site manager to confirm maximum delivery length before enquiry issue” is much more useful.
The document can remain short. Link supporting quotations and calculations instead of copying everything into it. What matters is that a colleague can trace a material cost decision without arranging a meeting with the person who made it.