40.5. The (In)Validity of Early Estimates
Garbage in, garbage out. Estimates done with unreliable and fuzzy information are unreliable and fuzzy. In the UP it is understood that estimates done during inception are not dependable (this is true of all methods, but the UP acknowledges it). Early inception estimates merely provide guidance if the project is worthy of some real investigation in elaboration, to generate a good estimate. After the first elaboration iteration there is some realistic information to produce a rough estimate. After the second iteration, the estimate starts to develop credibility (see Figure 40.4).
Figure 40.4. Estimation and project phases.
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Useful estimates require investment in some elaboration iterations. |