ABSTRACT
This chapter looks at a variety of different estimates and estimating types to ensure project managers have a sense of how the numbers might play out with different types of data. Ballpark, Scientific wild anatomical guess, and conceptual estimates are all terms for the guess—the most common estimate in all of project management. The estimates are built on information from experience and other sources, but very little in-depth analysis is actually taking place. Parametric estimates are based on simple parameters to establish the potential cost of an approach. The information they contain is normally rooted in some historical analysis of past projects, as well as critical features or factors that change the costs. Parametric estimates are models, built on historical experience, that are designed to afford the ability to perform quick evaluations of total project costs.
