The Discounted Cash Flow Rate of Return (DCFROR or Internal Rate of Return) is the most widely used decision criterion in the petroleum and mineral industries. However, its definition and significance are in dispute. Some authors claim that the DCFROR implicitly assumes that a project's intermediate cash flows will be immediately reinvested at a rate of interest equal to the project's DCFROR. A second group of analysts claim that, if a project's net cash flow series is correctly specified, the method makes no assumptions about the reinvestment of intermediate net cash receipts. A third group avoids the issue. Although this has been a heated debate, it appears to be an argument about semantics. The time value of money is one of the essential principles in financial analysis. The two most commonly used discounted cash flow decision criteria, net present value and DCFROR, are closely related. The calculation of these two criteria does not normally require consideration of reinvestment. However, this paper shows that there is also a close relationship between the reinvestment rate (RR), the growth rate of return (GROR), and DCFROR. This relationship can be used to compute DCFROR directly, and the method establishes a new definition for DCFROR, namely that reinvestment rate which makes RR=GROR=DCFROR.