Just want to know that Economic Value Add (EVA), IRR, NPV, Payback Period, PV and NPV are coming into which type ?

All above involve calculation. Are they coming under constrained optimization methods?

If yes, why does benefit to cost ratio come under benefit measurement methods?

[Answer]:
The Project selection methods IRR, NPV, Payback period, PV come under Benefit Measurement Methods, also known as Comparative approach and these are Cash Flow Analysis Techniques. It is not correct to think that just because these methods involve calculations, they fall under Mathematical Approach.

Examples of Mathematical approach (also known as Constrained optimization method) are: Linear Programming, Integer Programming, Dynamic Programming, Multi Objective Programming, and these methods use programming in the form of algorithms to arrive at the Project Selection. Its easier if you remember that Mathematical Approach involves complex mathematics and requires the use of a computer.