Perils of the Internal Rate of Return
The two most-used measures for evaluating an investment are the
net present value and the
internal rate of return. (Two earlier tutorials discussed these concepts. See the
tutorials list for links to tutorials for discounting future income and the internal rate of return.)
It is often assumed that higher is better for both of the net present value and the internal rate of return. In particular, it is usually stated that investments with higher internal rates of return are more profitable than investments with lower internal rates of return.
However, this is not necessarily so. In some situations, an investment with a lower internal rate of return may be better, even judged on narrow financial grounds, than an investment with a higher internal rate of return. This interactive lecture explores why and when this reversal takes place.
To review, both the net present value and