Shane Murphy: A Cambridge Time Estimate Should Name Its Assumptions

A time estimate can travel further than the explanation that produced it. Someone says a task should take a few days, and the phrase later appears in a schedule as though it were a confirmed delivery date. The conditions have disappeared, but the number remains. I think a useful estimate should carry its assumptions with it so that other people can understand what it does and does not mean.

I am Shane Murphy, also known as Shane Ian Murphy, formerly of Cambridge and formerly of Limitless Mobile, where I was co-founder and Chief Business Development Officer. This UK business commentary uses a hypothetical Cambridge display project. It does not report a real supplier commitment or recommend a timetable for a particular business.

Imagine a team asking a colleague how long it will take to prepare printed panels for a small exhibition. The colleague estimates the time needed to arrange the text and images. The coordinator hears a date by which the finished panels might be available. Both are discussing the same project, but they are measuring different parts of the work.

I would begin by naming the task included in the estimate. Does it cover preparing a draft, obtaining comments, making revisions or receiving the printed material? The description should identify a recognisable starting point and finishing point. Without those boundaries, a precise number can still be an imprecise answer.

Next, distinguish working time from elapsed time. A task may require several hours of attention while depending on a reply that arrives later. The team should understand which parts involve active work and which involve waiting for information or another person's action. This distinction can explain why a short task does not always fit into the next available afternoon.

The estimate should identify what must be ready before work begins. In our example, the colleague may need agreed text, usable images and the intended dimensions. If those inputs are still changing, the estimate should say how that affects the current understanding. Missing information should not be treated as though it has already arrived merely to make the schedule look complete.

I would also ask what level of revision has been assumed. An estimate for making small corrections differs from one that includes reconsidering the whole arrangement. The point is not to predict every comment in advance. It is to establish a shared picture of the work under discussion and identify the kind of change that would require a new conversation.

Where uncertainty is significant, the explanation should preserve it. A range can be useful if the team understands why its endpoints differ. A single date accompanied by a clear condition may be more appropriate in another situation. The form of the estimate should help the recipient make a decision; it should not create an appearance of certainty that the underlying information cannot support.

The coordinator needs to distinguish an estimate from an accepted commitment. Before communicating a delivery date to somebody else, they should confirm what has actually been agreed with the people responsible. A planning assumption should remain labelled as an assumption until that confirmation exists. This is a communication discipline, not a substitute for the organisation's own approval process.

I would record the estimate's date and the information on which it was based. If the panel dimensions change later, the team can see why an earlier estimate may no longer apply. A revised estimate should explain the relevant change rather than simply replacing one number with another. That preserves a usable account of how the plan developed.

The review should focus on what the new information means for the next action. Perhaps the team needs to finalise the text, obtain a different printing arrangement or discuss a revised event plan. Treating a changed estimate only as a performance judgement can distract from the practical question of how to proceed.

For the hypothetical Cambridge exhibition, a useful estimate helps people coordinate because they understand its boundaries. The task, starting conditions, expected revisions and external dependencies remain connected to the proposed timing. I would rather read an estimate with a short, clear explanation than inherit a confident date whose original meaning nobody can recover.

Author background: https://shanemurphy.co.uk/career

This author-origin business commentary was prepared with AI assistance.