scopeeconomics
Judge the information behind an estimate before deciding how it can be used.
The purpose of a cost estimate and the evidence behind it need to be considered together. A funding comparison made from broad capacity information is different from a tender estimate supported by coordinated drawings and supplier returns. Adding more decimal places does not change the underlying information.
AACE’s public 17R-97 sample identifies the maturity of project definition as the primary classification characteristic. Use the relevant published guidance when assigning a formal class. This lesson examines the judgement involved without reproducing the classification matrix or assigning universal accuracy percentages.
An early estimate can be useful for comparing options while still being unsuitable for placing a fixed-price order. State the decision it supports and identify the assumptions that could change the ranking. A number is not defective simply because it is uncertain; the problem is using it for a decision that its evidence cannot support.
For a proposed depot, a broad floor area and accommodation brief may support an initial option comparison. They do not establish foundation conditions, equipment interfaces or the construction sequence. List those gaps and explain how the estimate treats them. Do not hide them behind a classification label.
Ask which missing information would most improve the decision. For one project this may be ground information; for another it may be a major supplier clarification. A study plan should practise recognising those differences, not only recalling labels.
When explaining your answer, connect the source information to the proposed use. A good response might say that the model can support an early comparison, subject to the stated ground and servicing assumptions, and that further definition is needed before a procurement commitment. That reasoning is more informative than claiming a guaranteed accuracy range.
The client has a site boundary, a target floor area and a functional brief. Ground investigation, coordinated structural drawings and supplier returns are not yet available. The immediate decision is whether to develop one of two options.
| Available now | Still to establish |
|---|---|
| Target floor area | Coordinated quantities |
| Functional brief | Equipment and service interfaces |
| Site boundary | Ground and access constraints |
Original teaching example. This is an information comparison, not an AACE classification table.