Professional work often begins before every fact is available. A consultant may need to proceed on the basis of information expected from the client, a working interpretation of the brief or a condition that has not yet been confirmed. The problem is not using assumptions; it is allowing them to disappear into the analysis until later readers treat them as established facts. An assumption log keeps important uncertainty visible and manageable.
Record only assumptions that could affect the outcome
Focus on points that could change the analysis, recommendation, scope or deliverable if they prove wrong. Logging every minor expectation creates noise and makes the material assumptions harder to find.
Write assumptions so they can be tested
A useful entry states the working position clearly enough that someone can later confirm, reject or refine it. Avoid vague labels such as client situation unchanged. Identify the particular condition on which the work currently depends.
Explain why the assumption is necessary
Note the missing information, unresolved instruction or other reason the team cannot yet work from a confirmed fact. This helps colleagues distinguish a deliberate temporary assumption from an unsupported statement that slipped into the work accidentally.
Assign a route to confirmation
Where possible, identify how the assumption will be tested: client confirmation, receipt of a document, internal review or another appropriate source. If it cannot reasonably be confirmed, the team should decide how that limitation needs to be handled in the work.
Track the consequences of being wrong
Not all assumptions carry equal weight. Consider which parts of the engagement would need reconsideration if the working position changes. This helps the team prioritise follow-up on assumptions that have the greatest effect on the deliverable.
Retire assumptions when evidence arrives
Update an assumption once it is confirmed, disproved or replaced. Do not leave resolved entries looking active. Preserve enough history where useful, particularly if earlier work was completed under a different working position.
Review assumptions before conclusions are finalised
Before issuing a significant deliverable, scan the active assumptions and decide whether each is still acceptable. Material uncertainty may need further work, client confirmation or transparent treatment in the output. For small professional-services firms, this simple discipline helps prevent provisional thinking from quietly hardening into an unsupported conclusion.