One of the most dominant and serious complaints arising from the "software crisis" is the inability to estimate with acceptable accuracy the cost, resources, and schedule required for a software development. Traditional intuitive estimation methods have consistently produced optimistic results which contribute to the too familiar cost overrun and schedule slippage.

The rapidly increasing cost of software has led the customers for these products to become less willing to tolerate the uncertainty and losses associated with inaccurate cost and schedule estimates unless the developer is willing to accept a significant portion of that risk. This customer pressure emphasizes the need to use an estimation method that can be applied early in the software development where tradeoff studies and investment decisions are made. The estimation method must be able to consider the characteristics of the development organization and the environmental effects imposed by the development task, as well as the application size and complexity, in order to support reasonable estimates.

Several cost and schedule estimation methods have been proposed over the last 25 years with mixed success due, in part, to limitations of the estimation models. A significant part of the estimate failures can be attributed to a lack of understanding of the software development process and the impact of that process used in the schedule and cost estimates. One poorly understood variable in this process is the impact of management on the ultimate cost and schedule of the delivered product. The environment imposed by the project manager is a major driver in the software equation.