Thanks for spending time for answering my query. but i want to know how to calculate it . wht are its formulae. & how to implement it & at last how to use it in our audit.
Look at it this way an index is a statistical measure of change.
So, although I must confess (hence my reluctance to give a more elaborate explanation) to have never heard these terms before I could make a prudent guess to a reasonable certainty that they would imply what the situation (mostly likely in terms of money) was before relative to after the implementation of the control or the policy alternatively a comparative index between two time periods.