Estimation of a software project failure is based on project analogies in the area of software cost estimation. In all software cost estimation approaches important decisions must be made regarding certain approaches in order to obtain reliable estimate. A reliable and accurate estimate can be proved by simulation approach. A simulation modeling approach is proposed for the prediction of software effort productivity indices, such as cost and time-to-market, and the sensitivity analysis of such indices to changes in the organization parameters and user requirements. Simulation provides a controlled environment for evaluating performance. Changes can be made easily to the model and results evaluated quickly. In this paper we measure performance of VRS model through simulation result by comparing standard COCOMO Intermediate-Organic Model. This approach uses a model specification. Results demonstrate the model representativeness, and its usefulness in verifying process conformance to expectations, and in performing continuous process improvement and optimization.