Every well-run company that is considering making an investment in new equipment, a new facility, upgraded technology, or a new product or development project, considers at some level what return it will earn on that investment. They will often calculate Return on Investment (ROI), Discounted Cash Flow (DCF), Payback Period, or Internal Rate of Return (IRR). Oops! Wait! Most of them get that last one wrong. Often a well-intentioned analyst will calculate ROI and call it IRR, maybe because it sounds more technical or more elegant or whatever. But the calculation and the information conveyed are very different. Look at these definitions:

Return on Investment – a comparison of the total amount an investment will earn over its effective useful life compared to the total cost of that investment, expressed as a percent of that total cost. A simple enough calculation if you have the correct numbers.

Internal Rate of Return – that rate of return, stated as a percent, at which the return on the investment and the cost of capital used to make the investment are at least equal, with both at present value. Put another way, it’s the discount rate that makes the net present value of all cash flows from a particular project equal to or better than zero.

Big difference, huh? ROI does not consider the cost of the capital used to make the investment, only the earnings from it. And, there is no comparison to the cost of the money, or the significance of the time value of money. So, some lessons you can draw from this: First, Never invest in a project with a net present value less than zero or a negative IRR. Second, you can’t decide on the first until you actually do the math.