By Assoc. Prof. Dr. Ahmet ÖZTAŞ Gaziantep University Department of Civil Engineering CHP...

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ByAssoc. Prof. Dr. Ahmet ÖZTAŞ

Gaziantep UniversityDepartment of Civil Engineering

CHP IV-PRESENT WORTH ANALYSIS

CE 533 - ECONOMIC DECISION ANALYSIS IN CONSTRUCTION

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TOPICS

Formulating AlternativesPW of Equal-Life AlternativesPW of Different-Life alternativesFuture Worth AnalysisCapitalized Cost AnalysisIndependent projectsPayback Period

CHP IV-PRESENT WORTH ANALYSIS

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4.1 FORMULATING MUTUALLY EXCLUSIVE ALTERNATIVES

Viable firms/organizations have the capability to generate potential beneficial projects for potential investmentTwo types of investment categories Mutually Exclusive Set Independent Project Set

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4.1 FORMULATING MUTUALLY EXCLUSIVE ALTERNATIVES

Mutually Exclusive set is where a candidate set of alternatives exist (more than one)Objective: Pick one and only one from the set.Once selected, the remaining alternatives are excluded.

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4.1 INDEPENDENT PROJECT SET

Given a set of alternatives (more than one)The objective is to: Select the best possible combination of

projects from the set that will optimize a given criteria.

Subjects to constraints More difficult problem than the

mutually exclusive approach

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4.1 FORMULATING MUTUALLY EXCLUSIVE ALTERNATIVES

Mutually exclusive alternatives compete with each other.Independent alternatives may or may not compete with each otherThe independent project selection problem deals with constraints and may require a mathematical programming or bundling technique to evaluate.

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4.1 Type of Alternatives

Alternative’s CF are classified as revenue-based or cost-basedRevenue/Cost – the alternatives consist of cash inflow and cash outflows Select the alternative with the

maximum economic value

Service – the alternatives consist mainly of cost elements Select the alternative with the

minimum economic value (min. cost alternative)

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4.1 Evaluating Alternatives

Part of Engineering Economy is the selection and execution of the best alternative from among a set of feasible alternativesAlternatives must be generated from within the organization One of the roles of engineers!

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4.1 Evaluating Alternatives

In part, the role of the engineer to properly evaluate alternatives from a technical and economic viewMust generate a set of feasible alternatives to solve a specific problem/concern

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4.1 Alternatives

Problem

DoNothing

Alt.1

Alt.2

Alt.m

Analysis

Selection

Execution

If there are m investment proposals, we can form up to 2m mutually exclusive alternatives.This includes DN option.

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4.1 Alternatives: The Selected Alternative

Problem Alt.Selected

Execution

Audit and Track

Selection is dependent upon the data, life, discount rate, and assumptions made.

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4.2 Present Worth Approach Equal-Lifes

Simple – Transform all of the current and future estimated cash flow back to a point in time (time t = 0)

Have to have a discount rate before the analysis in started

Result is in equivalent dollars now!

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4.2 THE PRESENT WORTH METHOD

At an interest rate usually equal to or greater than the Organization’s established MARR.

A process of obtaining the equivalent worth of future cash flows to some point in time

– called the Present Worth

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4.2 THE PRESENT WORTH METHOD

P(i%) = P(+) – P(-).

P(i%) = P( + cash flows) + P( - cash flows)

OR, . . .

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4.2 THE PRESENT WORTH METHOD

If P(i%) > 0 then the project is deemed acceptable.

If P(i%) < 0 the project is usually rejected.

If P(i%) = 0 Present worth of costs = Present worth of revenues – Indifferent!

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4.2 THE PRESENT WORTH METHOD

If the present worth of a project turns out to = “0,” that means the project earned exactly the discount rate that was used to discount the cash flows!

The interest rate that causes a cash flow’s NPV to equal “0” is called the Rate of Return of the cash flow!

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4.2 THE PRESENT WORTH METHOD

A positive present worth is a dollar amount of "profit" over the minimum amount required by the investors (owners).

For P(i%) > 0, the following holds true:

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4.2 THE PRESENT WORTH METHOD – Depends upon the Discount Rate Used

The present worth is purely a function of the MARR (the discount rate one uses).If one changes the discount rate, a different present worth will result.

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4.2 THE PRESENT WORTH METHOD

For P(i%) > 0, the following holds true:

Acceptance or rejection of a project is a function of the timing and magnitude of the project's cash flows, and the choice of the discount rate.

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4.2 PRESENT WORTH: Special Applications

Present Worth of Equal Lived AlternativesAlternatives with unequal lives: BewareCapitalized Cost AnalysisRequire knowledge of the discount rate before we conduct the analysis

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4.2 PRESENT WORTH: Equal Lives

Present Worth of Equal Lived Alternatives – straightforward

Compute the Present Worth of each alternative and select the best, i.e., smallest if cost and largest if profit.

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4.2 Equal Lives – Straightforward!

Given two or more alternatives with equal lives….

Alt. 1

Alt. 2

Alt. N

N = for all alternative

s

Find PW(i%) for each alternative then compare

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4.2 PRESENT WORTH: Example

Consider: Machine AMachine B

First Cost $2,500 $3,500Annual Operating Cost 900

700Salvage Value 200 350Life 5 years 5 years

i = 10% per year

Which alternative should we select?

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4.2 PRESENT WORTH: Cash Flow Diagram

Which alternative should we select?

0 1 2 3 4 5

$2,500

A = $900

F5=$200MA

0 1 2 3 4 5

$3,500

F5=$350

A = $700

MB

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4.2 PRESENT WORTH: Solving

PA = 2,500 + 900 (P|A, .10, 5) – 200 (P|F, .01, 5)

= 2,500 + 900 (3.7908) - 200 (.6209) = 2,500 + 3,411.72 - 124.18 = $5,788

PB = 3,500 + 700 (P|A, .10, 5) –

350 (P|F, .10, 5) = 3,500 + 2,653.56 - 217.31 = $5,936SELECT MACHINE A: Lower PW cost!

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4.2 Present Worth of Bonds

Often corporations or government obtain investment capital for projects by selling bonds. A good application of PW method is the evaluation of a bond purchase alternative.If PW < 0 at MARR, do-nothing alternative is selected.A bond is similar to an IOU for time periods such as 5, 10, 20 or more years.

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4.2 Present Worth of Bonds

Each bond has a face value V of $100, $1000, $5000 or more that is fully returned to the purchaser when the bond maturity is reached.Additionaly, bond provide the purchaser with periodic interest payments I (bond dividends) using the bond coupon (interest) b, and c, the number of payment periods per year.

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4.2 Bonds – Notation and Example

(Bond face value)(bond coupon rate) V.bI = ------------------------------------------ = ---- number of payments per year c

At the time of purchase, the bond may sell for more or less than face value. Example:

V = $5,000 (face value) b = 4.5% per year paid semiannually c = 10 years

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4.2 PW Bonds – Example – Continued

The interest the firm would pay to the current bondholder is calculated as:

0.045$5,000( ) $5,000(0.0225)

2$112.50 every 6 months

I

I

The bondholder, buys the bond and will receive $112.50 every 6 months for the life of the bond

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4.2 Example 4.2

Ayşe has some extra money, requires safe investment. Her employer is offering to employees a generous 5% discount for 10-year 5000 YTL bonds tat carry a coupon rate of 6% paid semiannually. The expectation is to match her return on other safe investments, which have averaged 6.7% per year compounded semiannually. (This is an effective rate of 6.81% per year).

Should Ayşe buy the bond?

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4.2 Example 4.2 – Cash-Flow Diagram

A = 150

0 1 2 3 4 …. ….. 19 20

P=??

$5,000

i=3.35%

Find the PW(3.35%) of the future cash flows to the potential bond buyer

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4.2 Example 4.2 – Solving

I = (5000)(0.06)/2 = 150 YTL every 6 months for a total of n=20 dividend payments.The semiannual MARR is 6.7/2 = 3.35%, and the purchase price now is – 5000(0.95)= -4750 YTL.Using PW evaluation:PW = -4750 + 150(P/A, 3.35%, 20) + 5000(P/F, 3.35%, 20) = - 2.13 YTL <0Effective rate is slightly less than 6.81% per year since PW<0.She sould not buy.

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4.3 Present Worth Analysis of Different-Life Alternatives

In an analysis one cannot effectively compare the PW of one alternative with a study period different from another alternative that does not have the same study period.This is a basic rule!

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4.3 PRESENT WORTH: Unequal Lives

If the alternatives have different lifes, there are 2 ways to use PW analysis to compare alternatives:

A) The lowest common Multiple (LCM)

B) Study period (planning horizon)

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4.3 PRESENT WORTH: Lowest Common Multiple (LCM) of Lives

If the alternatives have different study periods, you find the lowest common life for all of the alternatives in question.Example: {3,4, and 6} years. The lowest common life (LCM) is 12 years.Evaluate all over 12 years for a PW analysis.

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4.3 PRESENT WORTH: Example Unequal Lives

EXAMPLEMachine A

Machine BFirst Cost $11,000 $18,000Annual Operating Cost 3,500

3,100Salvage Value 1,000 2,000Life 6 years 9 years

i = 15% per year

Note: Where costs dominate a problem it is customary to assign a positive value to cost and negative to inflows

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4.3 PRESENT WORTH: Example Unequal Lives

A common mistake is to compute the

present worth of the 6-year project and compare it to the

present worth of the 9-year project.NO! NO! NO!

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4.3 PRESENT WORTH: Unequal Lives

i = 15% per year

0 1 2 3 4 5 6

$11,000

F6=$1,000

A 1-6

=$3,500

Machine A

0 1 2 3 4 5 6 7 8 9

F6=$2,000

A 1-9

=$3,100

$18,000

Machine B

LCM(6,9) = 18 year study period will apply for present worth

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4.3 Unequal Lives: 2 Alternatives

i = 15% per year

Machine A

LCM(6,9) = 18 year study period will apply for present worth

Cycle 1 for A Cycle 2 for A Cycle 3 for A

6 years

6 years

6 years

Cycle 1 for B Cycle 2 for B

18 years

9 years 9 yearsMachine B

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4.3 Example: Unequal Lives Solving

LCM = 18 years

Calculate the present worth of a 6-year cycle for A

PA = 11,000 + 3,500 (P|A, .15, 6) –

1,000 (P|F, .15, 6) = 11,000 + 3,500 (3.7845) – 1,000 (.4323) = $23,813, which occurs at time 0, 6 and 12

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4.3 Example: Unequal Lives

PA= 23,813+23,813 (P|F, .15, 6)+

23,813 (P|F, .15, 12) = 23,813 + 10,294 + 4,451 = 38,558

0 6 12 18

$23,813 $23,813 $23,813

Machine A

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4.3 Unequal Lives Example: Machine B

Calculate the Present Worth of a 9-year cycle for B

0 1 2 3 4 5 6 7 8 9

F6=$2,000

A 1-9

=$3,100

$18,000

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4.3 9-Year Cycle for B

Calculate the Present Worth of a 9-year cycle for B

PB = 18,000+3,100(P|A, .15, 9) – 1,000(P|F, .15, 9) = 18,000 + 3,100(4.7716) -

1,000(.2843) = $32,508 which occurs at time 0 and

9

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4.3 Alternative B – 2 Cycles

PB = 32,508 + 32,508 (P|F, .15, 9)

= 32,508 + 32,508(.2843)

PB = $41,750

Choose Machine A

0 9 18

$32,508 $32,508

Machine A: PW =$38,558

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4.3 Unequal Lives – Assumed Study Period

Study Period Approach Assume alternative: 1 with a 5-year life Alternative: 2 with a 7-year life

Alt-1: N = 5 yrs

Alt-2: N= 7 yrs

LCM = 35 yrs

Could assume a study period of, say, 5 years.

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4.3 Unequal Lives – Assumed Study Period

Assume a 5-yr. Study periodEstimate a salvage value for the 7-year project at the end of t = 5Truncate the 7-yr project to 5 years

Alt-1: N = 5 yrs

Alt-2: N= 7 yrs

Now, evaluate both over 5 years using the PW method!

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FUTURE WORTH APPROACH

FW(i%) is an extension of the present worth methodCompound all cash flows forward in time to some specified time period using (F/P), (F/A),… factors or,Given P, the F = P(1+i)N

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Applications of Future Worth

Projects that do not come on line until the end of the investment period Commercial Buildings Marine Vessels Power Generation Facilities Public Works Projects

Key – long time periods involving construction activities

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Life Cycle Costs (LCC)

Extension of the Present Worth methodUsed for projects over their entire life span where cost estimates are employedUsed for: Buildings (new construction or

purchase) New Product Lines Commercial aircraft New automobile models Defense systems

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Life Cycle: Two General Phases

TIME

Cost-$

Acquisition Phase

Operation Phase

Cumulative Life Cycle Costs

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4.4 CAPITALIZED COST ANALYSIS

CAPITALIZED COST- the present worth of a project that lasts forever.Government ProjectsRoads, Dams, Bridges (projects that possess perpetual life)Infinite analysis period

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4.4 Derivation for Capitalized Cost

Start with the closed form for the P/A factor

Next, let N approach infinity and divide the numerator and denominator by (1+i)N

(1 ) 1

(1 )

N

N

iP A

i i

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4.4 Derivation - Continued

Dividing by (1+i)N yields

Now, let n approach infinity and the right hand side reduces to….

11

(1 )NiP A

i

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4.4 Derivation - Continued

1 AP A

i i

Or,

CC(i%) = A/i

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4.4 CAPITALIZED COST

Assume you are called on to maintain a cemetery site forever if the interest rate = 4% and $50/year is required to maintain the site.

Find the PW of an infinite annuity flow

1 2 3 4 5 ..

N=inf.

A=$50/yr

P = ?

…………………..

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4.4 CAPITALIZED COST

P0 = $50[1/0.04]

P0 = $50[25] = $1,250.00

Invest $1,250 into an account that earns 4% per year will yield $50 of interest forever if the fund is not touched and the i-rate stays constant.

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4.4 CAPITALIZED COST: Endowments

Assume a wealthy donor wants to endow a chair in an engineering department.

The fund should supply the department with $200,000 per year for a deserving faculty member.

How much will the donor have to come up with to fund this chair if the interest rate = 8%/yr.

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4.4 CAPITALIZED COST: Endowed Chair

The department needs $200,000 per year.

P = $200,000/0.08 = $2,500,000

If $2,500,000 is invested at 8% then the interest per year = $200,000

The $200,000 is transferred to the department, but the principal sum stays in the investment to continue to generate the required $200,000

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EXAMPLECalculate the Capitalized Cost of a project that has an initial cost of $150,000. The annual operating cost is $8,000 for the first 4 years and $5000 thereafter. There is an recurring $15,000 maintenance cost each 15 years. Interest is 15% per year.

4.4 Capitalized Cost Example

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$4,000

0 1 2 3 4 5 6 7 15 30 ………

$150,000

$8,000 $15,000 $15,000 $15,000 $15,000

“i”=15%/YR

N=

How much $$ at t = 0 is required to fund this project?

The capitalized cost is the total amount of $ at t = 0, when invested at the interest rate, will provide annual interest that covers the future needs of the project.

4.4 Cash Flow Diagram

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4.4 CAPITALIZED COST - Example Continued

1. Consider $4,000 of the $8,000 cost for the first four years to be a one-time cost, leaving a $4,000 annual operating cost forever.P0= 150,000 + 4,000 (P|A, .15, 4) =

$161,420

2.855

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4.4 CAPITALIZED COST - Continued

Recurring annual cost is $4,000 plus the equivalent annual of the 15,000 end-of-cycle cost.

…….0 15 30 45 60 ……..

Take any 15-year period and find the equivalent annuity for that period using the F/A factor.

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4.4 CAPITALIZED COST: One Cycle

Take any 15-year period and find the equivalent annuity for that period using the F/A factor

$15,000

A for a 15-year period

0 15 30 45 60 ……..

…….

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4.4 CAPITALIZED COST

2. Recurring annual cost is $4,000 plus the equivalent annual of the 15,000 end-of-cycle cost.

A= 4,000 + 15,000 (A|F, .15, 15)

= 4,000 + 15000 (.0210) = $5,315

Recurring costs = $5,315/i = 5,315/0.15 =$35,443/yr

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4.4 CAPITALIZED COST

Capitalized Cost = 161,420 + 5315/.15

= $196,853Thus, if one invests $196,853 at time t = 0, then the interest at 15% will supply the end-of-year cash flow to fund the project so long as the principal sum is not reduced or the interest rate changes (drops).

Another ExampleA wealthy businessman wants to start a permanent fund for supporting research directed toward sustainability. The donor plans to give equal amounts of money for each of the next 5 years, plus one now(i.e six donations) so that $100,000 per year can be withdrawn each year forever, beginning in year 6. If the fund earns interest at a rate of 8% per year, how much money must be donated each time?

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4.6 USING EXCEL FOR PW ANALYSIS

General format to determine the PW is;

PW = P – PV (i%,n,A,F)When different-life alternatives are evaluated using LCM; develop NPV functionPW = P + NPV(i%,year_1_CF_cell:last_year_CF_cell)

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Summary: Present Worth

• PW represents a family of methods

• Annual worth

• Future Worth

• Capitalized Cost

• Life-cycle cost analysis – application

• Bond Problems – application

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End of Chapter 4

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