ABSTRACT
The parametric estimating process is both simple and logical. Part of its beauty is the top-down nature of the approach. The model is not derived from the bottom-up approach which would have the potential for cost duplication and omissions. This is because the process is driven by determining the magnitude of the problem: for hardware the magnitude of the technology and the organization’s productivity and for software the organization productivity and size. You don’t enter costs, non-cost data is entered and costs are created. The process for estimating cost and schedule involves four simple stages:
determine the system architecture in a breakdown structure;
identify the project parameters for the elements of the system;
determine the cost and schedule drivers of the elements of the system;
run the model, validate the results and present the answers.
