PFE, Chapter 3: Capital budgeting 12
3.5. Do NPV and IRR produce the same project rankings?
In the previous section we saw that for conventional projects, NPV and IRR give the
same “Yes-No” answer about whether to invest in a project. In this section we’ll see that NPV
and IRR do not necessarily rank projects the same, even if the projects are both conventional.
Suppose we have two projects and can choose to invest in only one. The projects are
mutually exclusive: They are both ways to achieve the same end, and thus we would choose only
one. In this section we discuss the use of NPV and IRR to rank the projects. To sum up our
results before we start:
• Ranking projects by NPV and IRR can lead to possibly contradictory results. Using the
NPV criterion may lead us to prefer one project whereas using the IRR criterion may lead
us to prefer the other project.
• Where a conflict exists between NPV and IRR, the project with the larger NPV is
preferred. That is, the NPV criterion is the correct criterion to use for capital budgeting.
This is not to impugn the IRR criterion, which is often very useful. However, NPV is
preferred over IRR because it indicates the increase in wealth which the project produces.
An example
Below we show the cash flows for Project A and Project B. Both projects have the same
initial cost of $500, but have different cash flow patterns. The relevant discount rate is 15
percent.