It is very difficult to make a vigorous, plausible, and job-risking defense of an estimate that is derived by no quantitative method, supported by little data, and certified chiefly by the hunches of the managers.
You might think you already know what an estimate is. My goal by the end of this chapter is to convince you that an estimate is different from what most people think. A good estimate is even more different.
Here is a dictionary definition of estimate: 1. A tentative evaluation or rough calculation. 2. A preliminary calculation of the cost of a project. 3. A judgment based upon one’s impressions; opinion. (Source: The American Heritage Dictionary, Second College Edition, 1985.)
Does this sound ...