Practical working guide
An estimate assumptions register for uncertain service work
An estimate assumptions register lists the unverified conditions behind a proposed scope, their possible impact and how they will be checked. Use it before commitment so uncertainty is visible. It complements the estimate; it is not permission to add charges or change agreed work.
Copy the register
| Assumption | Details |
|---|---|
| Existing substrate is sound | Evidence needed: Inspection before installation Impact if false: Different preparation may be needed Owner and decision point: Site lead, before final scope |
| Customer can provide access | Evidence needed: Confirmed access window Impact if false: Proposed date may not work Owner and decision point: Coordinator, before booking |
| Specified part is available | Evidence needed: Supplier confirmation Impact if false: Alternative needs review Owner and decision point: Buyer, before ordering |
Work an uncertainty through to a decision
Fictional example: a flooring estimate assumes a dry, sound base. Inspection finds damage. Change the assumption status to “disproved”, attach the inspection evidence and pause the affected scope decision. Describe the alternative preparation separately for review. Do not silently replace the original estimate or let the delivery team treat an unapproved option as agreed work.
Close the loop before handoff
Give every row a status: unverified, confirmed, disproved or no longer relevant, with date and evidence. Separate an assumption from an exclusion: an exclusion says what the offer does not include. Before handoff, highlight any unresolved condition and its agreed handling. If scope has already been accepted, use the change process rather than rewriting history.