The document discusses internal rate of return (IRR) and real options for evaluating investment projects. IRR is the discount rate that makes the net present value of a project equal to zero. It is calculated through trial and error by changing the discount rate in the NPV equation until NPV equals zero. Real options view some investments, like R&D, as analogous to stock options where the initial investment is like an option premium and future investments to commercialize the technology are like the exercise price. Real options analysis can provide additional insights for investment decisions compared to traditional net present value analysis.