Help me critique this post and add two points to it: Businesses use a few tools to evaluate the profits generated from a project or investment. The net present value (NPV) is one of those methods. NPV calculates the present value of the project's cash inflows less the present value of its cash outflows. NPV is the preferred method when selecting projects because its calculation captures the value in dollars today of the gain or loss a project will generate that is over and above the required rate of return. The NPV method allows multiple projects to be combined to review a portfolio of projects. NPV can also be expressed as a unique number, enabling the company to make an accurate assessment of the financial results that can help in the decision to accept or reject a project. Also, if the discount rate changes, this method will produce different results for the same project. The NPV method considers both the before and the after cash flow over the project's life span. This method assumes that the project cash flows can only be reinvested at the company's required rate of return. This method sometimes makes calculating the appropriate discount rate for cash flows complicated. Another tool is the internal rate-of-return (IRR) calculation. IRR is the method that is the most widely used. Its calculation results in a percentage that is easy to understand and compare. Internal rate-of-return is the discount rate that makes the net present value equal to zero. The results of IRR for multiple projects cannot be added together for a portfolio of projects, and this method cannot be used in evaluating projects with changing cash flows. IRR will provide a business with sound guidance on a project's value and associated risk. With this method, you can have more than one IRR for a single project. With IRR, if the discount rate changes, the results will remain the same. This method implicitly assumes that the project cash flows can be invested at the project's rate of return, leading to erroneous decisions