•ROI =
(Benefits-Costs)/Costs
•NPV = The equation for a three year NPV is:
(net benefit year 1 /
(1+discount rate) + net benefit year 2 / (1+discount rate)^2 + net benefit year 3 / (1+discount rate)^3) - initial costs
… Discounted Cash Flow Model
•IRR à NPV = 0 e.g. 3-year model:
initial costs = net benefit year 1 / (1+IRR) + net benefit year 2 / (1+IRR)^2 + net benefit year 3 / (1+IRR)^3