An appraisal is a set of assumptions presented as a number. Before capital is committed, each of those assumptions should be traced back to the site and the scheme.
Is the revenue supported by the mix and the market? Is the build cost consistent with the programme? Does the programme reflect the constraints on site? Is finance modelled on the real cash flow? And where is the return most sensitive?
The answers are rarely in one document. They sit across the design, the cost plan, the programme and the model, which is why they are best read together.