The importance of software cost estimation has been increasing gradually over last three decades. Software cost estimation is related to how long and how many people are required to complete a software project. Software cost estimation is the process of predicting the effort and cost required to develop a software system. The basic input for the software cost estimation is coding size and set of cost drivers, the output is effort in terms of Person-Months (PM’s) and cost. One of the problems in software cost estimation is how the authors can evaluate the cost estimation model.