Profitability index

Profitability index (PI), also known as profit investment ratio (PIR) and value investment ratio (VIR), is the ratio of investment to payoff of a proposed project. It is a useful tool for ranking projects because it allows you to quantify the amount of value created per unit of investment.

The ratio is calculated as follows:

• ${\text{Profitability index}}={\frac {\text{PV of future cash flows}}{\text{Initial investment}}}$

Assuming that the cash flow calculated does not include the investment made in the project, a profitability index of 1 indicates breakeven. Any value lower than one would indicate that the project's PV is less than the initial investment. As the value of the profitability index increases, so does the financial attractiveness of the proposed project.

Rules for selection or rejection of a project:

• If PI > 1 then accept the project
• If PI < 1 then reject the project

For example, given:

• Investment = 40,000
• life of the Machine = 5 Years

CFAT Year      CFAT

      1        18000
      2        12000
      3        10000
      4         9000
      5         6000

Calculate Net present value at 10% and PI:

     Year      CFAT      PV@10%       PV

      1        18000      0.909      16362 
      2        12000      0.827       9924   
      3        10000      0.752       7520
      4         9000      0.683       6147     
      5         6000      0.621       3726
              Total present value    43679
              (-) Investment         40000
                         NPV           3679

                         PI =  43679 / 40000
                            =  1.091
                            = >1 
                            = Accept the project

External links

Detailed discussion on PI from an industry expert

Definition from Investopedia

Profitability Index Calculator

Use explained in the business book: Pursuing the Competitive Edge, Hayes, Pisano, Upton and Wheelwright. Wiley, 2005. pg. 264