• • • Net present value (NPV) and internal rate of return (IRR) are two very practical discounted cash flow (DCF) calculations used for making capital budgeting decisions. NPV and IRR lead to the same decisions with investments that are independent. With mutually exclusive investments, the NPV method is easier to use and more reliable.
To this point neither of the two discounted cash flow procedures for evaluating an investment is obviously incorrect. In many situations, the internal rate of return (IRR) procedure will lead to the same decision as the net present value (NPV) procedure, but there are also times when the IRR may lead to different decisions from those obtained by using the net present value procedure. When the two methods lead to different decisions, the net present value method tends to give better decisions. It is sometimes possible to use the IRR method in such a way that it gives the same results as the NPV method. For this to occur, it is necessary that the rate of discount at which it is appropriate to discount future cash proceeds be the same for all future years. If the appropriate rate of interest varies from year to year, then the two procedures may not give identical answers. It is easy to use the NPV method correctly. It is much more difficult to use the IRR method correctly.
Accept or Reject Decisions
Frequently, the investment decision to be made is whether to accept or reject a project where the cash flows of the project do not affect the cash flows of other projects. We speak of this type of investment as being an independent investment. With the IRR procedure, the recommendation with conventional cash flows is to accept an independent investment if its IRR is greater than some minimum acceptable rate of discount. If the cash flow corresponding to the investment consists of one or more periods of cash outlays