1. Contemporary Engineering Economics, 4 th edition, © 2007 Incremental Analysis Lecture No. 28 Chapter 7 Contemporary Engineering Economics Copyright © 2006

2. Contemporary Engineering Economics, 4 th edition, © 2007 Comparing Mutually Exclusive Alternatives Based on IRR Issue: Can we rank the mutually exclusive projects by the magnitude of its IRR? nA1A2 0 1 IRR -$1,000-$5,000 $2,000$7,000 100% > 40% $818<$1,364 PW (10%)

3. Contemporary Engineering Economics, 4 th edition, © 2007 Who Got More Pay Raise? BillHillary 10%5%

4. Contemporary Engineering Economics, 4 th edition, © 2007 Can’t Compare without Knowing Their Base Salaries BillHillary Base Salary$50,000$200,000 Pay Raise (%)10%5% Pay Raise ($)$5,000$10,000 For the same reason, we can’t compare mutually exclusive projects based on the magnitude of its IRR. We need to know the size of investment and its timing of when to occur.

5. Contemporary Engineering Economics, 4 th edition, © 2007 Incremental Investment Assuming a MARR of 10%, you can always earn that rate from other investment source, i.e., $4,400 at the end of one year for $4,000 investment. By investing the additional $4,000 in A2, you would make additional $5,000, which is equivalent to earning at the rate of 25%. Therefore, the incremental investment in A2 is justified. nProject A1Project A2 Incremental Investment (A2 – A1) 0101 -$1,000 $2,000 -$5,000 $7,000 -$4,000 $5,000 ROR PW(10%) 100% $818 40% $1,364 25% $546

6. Contemporary Engineering Economics, 4 th edition, © 2007 Incremental Analysis (Procedure) Step 1:Compute the cash flow for the difference between the projects (A,B) by subtracting the cash flow of the lower investment cost project (A) from that of the higher investment cost project (B). Step 2:Compute the IRR on this incremental investment (IRR ). Step 3:Accept the investment B if and only if IRR B-A > MARR B-A NOTE: Make sure that both IRR A and IRR B are greater than MARR.

7. Contemporary Engineering Economics, 4 th edition, © 2007 Example 7.10 - Incremental Rate of Return nB1B2B2 - B1 01230123 -$3,000 1,350 1,800 1,500 -$12,000 4,200 6,225 6,330 -$9,000 2,850 4,425 4,830 IRR25%17.43%15% Given MARR = 10%, which project is a better choice? Since IRR B2-B1 =15% > 10%, and also IRR B2 > 10%, select B2.

8. Contemporary Engineering Economics, 4 th edition, © 2007 IRR on Increment Investment: Three Alternatives nD1D2D3 0-$2,000-$1,000-$3,000 11,5008001,500 21,0005002,000 38005001,000 IRR34.37%40.76%24.81% Step 1: Examine the IRR for each project to eliminate any project that fails to meet the MARR. Step 2: Compare D1 and D2 in pairs. IRR D1-D2 =27.61% > 15%, so select D1. D1 becomes the current best. Step 3: Compare D1 and D3. IRR D3-D1 = 8.8% < 15%, so select D1 again. Here, we conclude that D1 is the best alternative.

9. Contemporary Engineering Economics, 4 th edition, © 2007 Practice Problem You are considering four types of engineering designs. The project lasts 10 years with the following estimated cash flows. The interest rate (MARR) is 15%. Which of the four is more attractive? Project ABCD Initial cost $150$220$300$340 Revenues/ Year $115$125$160$185 Expenses/ Year $70$65$60$80 IRR (%) 27.3224.1331.1128.33

10. Contemporary Engineering Economics, 4 th edition, © 2007 ItemsCMS OptionFMS Option Annual O&M costs: Annual labor cost$1,169,600$707,200 Annual material cost832,320598,400 Annual overhead cost 3,150,0001,950,000 Annual tooling cost470,000300,000 Annual inventory cost141,00031,500 Annual income taxes1,650,0001,917,000 Total annual costs$7,412,920$5,504,100 Investment$4,500,000$12,500,000 Net salvage value$500,000$1,000,000 Example 7.13 Incremental Analysis for Cost-Only Projects

11. Contemporary Engineering Economics, 4 th edition, © 2007 nCMS OptionFMS Option Incremental (FMS-CMS) 0-$4,500,000-$12,500,000-$8,000,000 1-7,412,920-5,504,1001,908,820 2-7,412,920-5,504,1001,908,820 3-7,412,920-5,504,1001,908,820 4-7,412,920-5,504,1001,908,820 5-7,412,920-5,504,1001,908,820 6-7,412,920-5,504,100 $2,408,820 Salvage+ $500,000+ $1,000,000 Incremental Cash Flow (FMS – CMS)

12. Contemporary Engineering Economics, 4 th edition, © 2007 Solution:

13. Contemporary Engineering Economics, 4 th edition, © 2007 Example 7.14 IRR Analysis for Projects with Different Lives MARR = 15%  The incremental cash flows (Model B – Model A) result in a nonsimple and mixed investment.  RIC B–A = 50.68% > 15%  Select Model B

14. Contemporary Engineering Economics, 4 th edition, © 2007 Summary Rate of return (ROR) is the interest rate earned on unrecovered project balances such that an investment’s cash receipts make the terminal project balance equal to zero. Rate of return is an intuitively familiar and understandable measure of project profitability that many managers prefer to NPW or other equivalence measures. Mathematically we can determine the rate of return for a given project cash flow series by locating an interest rate that equates the net present worth of its cash flows to zero. This break-even interest rate is denoted by the symbol i*.

15. Contemporary Engineering Economics, 4 th edition, © 2007 Internal rate of return (IRR) is another term for ROR that stresses the fact that we are concerned with the interest earned on the portion of the project that is internally invested, not those portions that are released by (borrowed from) the project. To apply rate of return analysis correctly, we need to classify an investment into either a simple or a nonsimple investment. A simple investment is defined as one in which the initial cash flows are negative and only one sign change occurs in the net cash flow, whereas a nonsimple investment is one for which more than one sign change occurs in the net cash flow series. Multiple i*s occur only in nonsimple investments. However, not all nonsimple investments will have multiple i*s either.

16. Contemporary Engineering Economics, 4 th edition, © 2007 For a pure investment, the solving rate of return (i*) is the rate of return internal to the project; so the decision rule is: If IRR > MARR, accept the project. If IRR = MARR, remain indifferent. If IRR < MARR, reject the project. IRR analysis yields results consistent with NPW and other equivalence methods. For a mixed investment, we need to calculate the true IRR, or known as the “return on invested capital.” However, if your objective is simply to make an accept or reject decision, it is recommended that either the NPW or AE analysis be used to make an accept/reject decision. To compare mutually exclusive alternatives by the IRR analysis, the incremental analysis must be adopted.