Analogous estimating is a technique for estimating a variety of project parameters and measures of scale. The project parameters that can be measured include those of project cost, project budget, scope of the project, and expected project duration. The project measures that can be estimated using this technique can range from the size of the project, to the project weight, to the complexity. The estimates are made by comparing the current activity to that of a smaller activity that took place previously and drawing comparisons in proportion to that. It is frequently used to estimate the size of a particular parameter when information as to that particular parameter within the current project is limited or unavailable until a later date. Analogous estimating is typically a form of expert judgment that is most reliable not only when the previous activities are similar to the current activity in fact, and not just in appearance, and also is traditionally most effective when the team members preparing the estimates have the expertise necessary to accurately do so.
This term is defined in the 3rd and the 4th edition of the PMBOK.