A plethora of software estimation tools are available, each claimed to be better than the others, thereby confusing prospective buyers. An effective tool ought to provide for all four aspects of software estimation, namely, size, effort, cost, and schedule.
such as software maintenance, enterprise resource planning (ERP) implementation, and testing projects, are not full software development life cycle (SDLC) projects. The software estimation tool has to cater to these projects too, using such techniques as task-based estimation. Task-based estimation is parameterized so that different project types can be defined and used by the organization. Therefore, the twelfth criterion for selecting a software estimation tool is the tool must cater to part life cycle