Requirement Stability Index:

Requirement Stability Index:

It’s a measure that quantifies the cumulative degree to which the requirements changed throughout the life cycle of the project from original requirement baseline.

                                  RSI = (R_T -  R_C )/ R_T 

               R_T = Total number of requiremnets baselined at the beginning of project

               R_C = Total number of changes to the original baselined requirements and

                                 R_C  = R_{a  +} R_m + R_r 

               R_a = Number of new requirements added to the original baselined requirements.

               R_m = Number of requirements modified to the original baselined requirements.

               R_r = Number of requirements removed from the original baselined requirements.