Causes of Estimation Error
As revealed by Jones (1994) and many other experts, both IT and business project teams have an extremely poor track record in the area of estimation. However, unlike many other experts, we believe that IT people, in particular, are very good at estimating. Other factors just confuse the estimation process. In fact, it is our experience that the factors covered in the following sections are the most significant causes of estimation error.
Misestimating the Scope
This is such an obvious problem that it is amazing it still is a problem in business and IT projects. As shown in Figure 14.2, Barry Boehm's (1989) research shows that the average estimation error in estimates made before the project's scope and objectives are ...