Software reliability is the probability of failure free software which work for a specified period of time in a specified environment. Software Reliability is also an important factor affecting system reliability. In the existing, software management approaches like CMM and SPICE gives the quantitative model of software process management. But these methods are based on the accuracy and the reliability of the input data to the system. This paper estimates the reliability factor issues of data for different metrics of software process model under different criteria. This paper is a survey which can be used to design a reliability system based on soft technique.