Return on investment (ROI) is a financial calculation that measures the profitability of a solution proposal by comparing its benefits and costs. ROI is expressed as a percentage or a ratio of the net benefits (benefits minus costs) to the total costs. ROI can help to determine which solution is worth investing in based on its breakeven point, which is the point where the net benefits equal zero, or the benefits equal the costs. The solution with the highest ROI has the lowest breakeven point, meaning that it recovers its costs faster and generates more net benefits over time. Discount rate is a financial calculation that measures the present value of future cash flows by applying a discount factor that reflects the time value of money and the risk of the investment. Discount rate can help to compare the present values of different solution proposals, but it does not indicate the breakeven point. Net present value (NPV) is a financial calculation that measures the difference between the present value of the benefits and the present value of the costs of a solution proposal. NPV can help to determine which solution has the highest value in today’s terms, but it does not indicate the breakeven point. Internal rate of return (IRR) is a financial calculation that measures the annualized effective compounded return rate of a solution proposal by finding the discount rate that makes the NPV equal zero. IRR can help to determine which solution has the highest return rate, but it does not indicate the breakeven point. References: BABOK Guide v3, Chapter 10: Techniques, Section 10.23: Financial Analysis, p. 529-531; Free CBAP IIBA Actual Exam Questions & Answers, Question 464.