ABSTRACT
The purpose of the cone model is to emphasize that it is only over time and experience that readers gain precision in their ability to estimate the cost of the true requirements of the project, and so the variability of our estimates converge to their true values over time. There is a fundamental relationship between time, cost, and functionality. Project managers sometimes refer to this triad as the three legs of the project management stool. Value engineering occurs throughout the system life cycle and is typically considered a project management activity. One of the most widely used software cost and effort estimation tools is Boehm's COCOMO model, first introduced in 1981. COCOMO models are based on an estimate of lines of code, modified by a number of factors. WEBMO is a derivative of COCOMO that is intended specifically for project estimation of Web-based projects, where COCOMO is not always as good.
