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Department of Civil and Environmental Engineering

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1 1.040/1.401 Project Management Spring 2006 Risk Analysis Decision making under risk and uncertainty
Department of Civil and Environmental Engineering Massachusetts Institute of Technology

2 Preliminaries Announcements Construction nightmares discussion
Remainder Sharon Lin the team info by midnight, tonight Monday Feb 27 - Student Experience Presentation Wed March 1st – Assignment 2 due Today, recitation Joe Gifun, MIT facility Next Friday, March 3rd, Tour PDSI construction site 1st group noon – 1:30 2nd group 1:30 – 3:00 Construction nightmares discussion 16 - Psi Creativity Center, Design and Bidding phases

3 Project Management Phase
DESIGN PLANNING FEASIBILITY DEVELOPMENT CLOSEOUT OPERATIONS Financing&Evaluation Risk Analysis&Attitude

4 Risk Management Phase Risk management (guest seminar 1st wk April)
RISK MNG DESIGN PLANNING FEASIBILITY DEVELOPMENT CLOSEOUT OPERATIONS Risk management (guest seminar 1st wk April) Assessment, tracking and control Tools: Risk Hierarchical modeling: Risk breakdown structures Risk matrixes Contingency plan: preventive measures, corrective actions, risk budget, etc.

5 Decision Making Under Risk Outline
Risk and Uncertainty Risk Preferences, Attitude and Premiums Examples of simple decision trees Decision trees for analysis Flexibility and real options

6 Decision making

7 Uncertainty and Risk “risk” as uncertainty about a consequence
Preliminary questions What sort of risks are there and who bears them in project management? What practical ways do people use to cope with these risks? Why is it that some people are willing to take on risks that others shun?

8 Some Risks Weather changes Community opposition Different productivity
(Sub)contractors are Unreliable Lack capacity to do work Lack availability to do work Unscrupulous Financially unstable Late materials delivery Lawsuits Labor difficulties Unexpected manufacturing costs Failure to find sufficient tenants Community opposition Infighting & acrimonious relationships Unrealistically low bid Late-stage design changes Unexpected subsurface conditions Soil type Groundwater Unexpected Obstacles Settlement of adjacent structures High lifecycle costs Permitting problems

9 Importance of Risk Much time in construction management is spent focusing on risks Many practices in construction are driven by risk Bonding requirements Insurance Licensing Contract structure General conditions Payment Terms Delivery Method Selection mechanism

10 Outline Risk and Uncertainty Risk Preferences, Attitude and Premiums
Examples of simple decision trees Decision trees for analysis Flexibility and real options

11 Decision making under risk Available Techniques
Decision modeling Decision making under uncertainty Tool: Decision tree Strategic thinking and problem solving: Dynamic modeling (end of course) Fault trees

12 Introduction to Decision Trees
We will use decision trees both for Illustrating decision making with uncertainty Quantitative reasoning Represent Flow of time Decisions Uncertainties (via events) Consequences (deterministic or stochastic)

13 Decision Tree Nodes Decision (choice) Node Chance (event) Node
Time Decision (choice) Node Chance (event) Node Terminal (consequence) node Outcome (cost or benefit) Note probabilities associated with events Note consequences associated with terminal nodes

14 Risk Preference People are not indifferent to uncertainty
Lack of indifference from uncertainty arises from uneven preferences for different outcomes E.g. someone may dislike losing $x far more than gaining $x value gaining $x far more than they disvalue losing $x. Individuals differ in comfort with uncertainty based on circumstances and preferences Risk averse individuals will pay “risk premiums” to avoid uncertainty Stress that Risk Applies to other concepts than money

15 Risk preference The preference depends on decision maker point of view

16 Categories of Risk Attitudes
Risk attitude is a general way of classifying risk preferences Classifications Risk averse fear loss and seek sureness Risk neutral are indifferent to uncertainty Risk lovers hope to “win big” and don’t mind losing as much Risk attitudes change over Time Circumstance

17 Decision Rules The pessimistic rule (maximin = minimax)
The conservative decisionmaker seeks to: maximize the minimum gain (if outcome = payoff) or minimize the maximum loss (if outcome = loss, risk) The optimistic rule (maximax) The risklover seeks to maximize the maximum gain Compromise (the Hurwitz rule): Max (α min + (1- α) max) , 0 ≤ α ≤ 1 α = 1 pessimistic α = 0.5 neutral α = 0 optimistic

18 The bridge case – unknown prob’ties
$ 1.09 million replace $1.61 M $0.55 $1.43 repair Investment PV Pessimistic rule min (1, 1.61) = 1 replace the bridge The optimistic rule (maximax) max (1, 0.55) = 0.55 repair … and hope it works!

19 The bridge case – known prob’ties
$ 1.09 million replace $1.61 M $0.55 $1.43 0.25 repair 0.5 Investment PV 0.25 Expected monetary value E = (0.25)(1.61) + (0.5)(0.55) + (0.25)(1.43) = $ 1.04 M Data link

20 The bridge case – decision
The pessimistic rule (maximin = minimax) Min (Ei) = Min (1.09 , 1.04) = $ 1.04 repair In this case = optimistic rule (maximax) Awareness of probabilities change risk attitude

21 Other criteria Most likely value Expected value of Opportunity Loss
For each policy option we select the outcome with the highest probability Expected value of Opportunity Loss

22 To buy soon or to buy later
-100 Buy soon = -125 = -95 = -65 Buy later Current price = 100 S1 = + 30% S2 = no price variation S3 = - 30% Actualization = 5

23 To buy soon or to buy later
-100 Buy soon -125 -95 -65 Buy later 0. 5 0.25 0.25

24 The Utility Theory When individuals are faced with uncertainty they make choices as is they are maximizing a given criterion: the expected utility. Expected utility is a measure of the individual's implicit preference, for each policy in the risk environment. It is represented by a numerical value associated with each monetary gain or loss in order to indicate the utility of these monetary values to the decision-maker.

25 Adding a Preference function
1.35 1 .7 125 100 65 Expected (mean) value E = (0.5)(125) + (0.25)(95) + (0.25)(65) = Utility value: f(E) = ∑ Pa * f(a) = 0.5 f(125) f(95) f(65) = = .5* * *1.35 = ~0.95 Certainty value = *0.975 = If 2 strategies have the same EMV, one can take decision only by preference multiplying factor

26 Defining the Preference Function
Suppose to be awarded a $100M contract price Early estimated cost $70M What is the preference function of cost? Preference means utility or satisfaction utility 70 $

27 Notion of a Risk Premium
A risk premium is the amount paid by a (risk averse) individual to avoid risk Risk premiums are very common – what are some examples? Insurance premiums Higher fees paid by owner to reputable contractors Higher charges by contractor for risky work Lower returns from less risky investments Money paid to ensure flexibility as guard against risk

28 Conclusion: To buy or not to buy
The risk averter buys a “future” contract that allow to buy at $ 97.38 The trading company (risk lover) will take advantage/disadvantage of future benefit/loss

29 Certainty Equivalent Example
Consider a risk averse individual with preference fn f faced with an investment c that provides 50% chance of earning $20000 50% chance of earning $0 Average money from investment = .5*$20,000+.5*$0=$10000 Average satisfaction with the investment= .5*f($20,000)+.5*f($0)=.25 This individual would be willing to trade for a sure investment yielding satisfaction>.25 instead Can get .25 satisfaction for a sure f-1(.25)=$5000 We call this the certainty equivalent to the investment Therefore this person should be willing to trade this investment for a sure amount of money>$5000 Mean satisfaction with investment .50 .25 Certainty equivalent of investment Mean value Of investment Risk averse individual .25 only corresponded to SURE return of $5000 Should be willing to trade this investment for a SURE investment that returns anything more than 5,000 this would be a gain for the this party, because would be HAPPIER with it than with the unsure investment shown here this could be a gain for another party who is less risk averse, because get MORE MONEY for the trade $5000

30 Example Cont’d (Risk Premium)
The risk averse individual would be willing to trade the uncertain investment c for any certain return which is > $5000 Equivalently, the risk averse individual would be willing to pay another party an amount r up to $5000 =$10000-$5000 for other less risk averse party to guarantee $10,000 Assuming the other party is not risk averse, that party wins because gain r on average The risk averse individual wins b/c more satisfied Stress that the reason for willingness to trade is that thee satisfaction resulting from a certain return >$5000 is > .25 Guarantor is given $2K automatically if $20000 comes in, gives $10000 to risk averse party: make $10K+2K= 12K if 0 comes in , give $10K to risk averse party; make -10K+2K = -8K therefore on average, make (12K-8K)/2= 2K

31 Certainty Equivalent More generally, consider situation in which have
Uncertainty with respect to consequence c Non-linear preference function f Note: E[X] is the mean (expected value) operator The mean outcome of uncertain investment c is E[c] In example, this was .5*$20,000+.5*$0=$10,000 The mean satisfaction with the investment is E[f(c)] In example, this was .5*f($20,000)+.5*f($0)=.25 We call f-1(E[f(c)]) the certainty equivalent of c Size of sure return that would give the same satisfaction as c In example, was f-1(.25)=f-1(.5*20,000+.5*0)=$5,000 Use term “mean” rather than expected value

32 Risk Attitude Redux The shapes of the preference functions means can classify risk attitude by comparing the certainty equivalent and expected value For risk loving individuals, f-1(E[f(c)])>E[c] They want Certainty equivalent > mean outcome For risk neutral individuals, f-1(E[f(c)])=E[c] For risk averse individuals, f-1(E[f(c)])<E[c]

33 Motivations for a Risk Premium
Consider Risk averse individual A for whom f-1(E[f(c)])<E[c] Less risk averse party B A can lessen the effects of risk by paying a risk premium r of up to E[c]-f-1(E[f(c)]) to B in return for a guarantee of E[c] income The risk premium shifts the risk to B The net investment gain for A is E[c]-r, but A is more satisfied because E[c] – r > f-1(E[f(c)]) B gets average monetary gain of r

34 Gamble or not to Gamble Preference function f(-1)=0, f(1)=100
EMV (0.5)(-1) + (0.5)(1) = 0 Preference function f(-1)=0, f(1)=100 Certainty eq. f-1(E[f(c)]) = 0 No help from risk analysis !!!!!

35 Multiple Attribute Decisions
Frequently we care about multiple attributes Cost Time Quality Relationship with owner Terminal nodes on decision trees can capture these factors – but still need to make different attributes comparable

36 The bridge case - Multiple tradeoffs
Computation of Pareto-Optimal Set For decision D2 Replace MTTF Cost 1.00 C3 MTTF Cost 0.30 C4 MTTF Cost 0.00 Aim: maximizing bridge duration, minimizing cost MTTF = mean time to failure

37 Pareto Optimality Even if we cannot directly weigh one attribute vs. another, we can rank some consequences Can rule out decisions giving consequences that are inferior with respect to all attributes We say that these decisions are “dominated by” other decisions Key concept here: May not be able to identify best decisions, but we can rule out obviously bad A decision is “Pareto optimal” (or efficient solution) if it is not dominated by any other decision Mention one decision low in cost, high in time One decision high in cost, low in time Point is that in decision analysis, only consider pareto optimal

38 03/06/06 - Preliminaries Announcements Reading questions/comments?
Due dates Stellar Schedule and not Syllabus Term project Phase 2 due March 17th Phase 3 detailed description posted on Stellar, due May 11 Assignment PS3 posted on Stellar – due date March 24 Decision making under uncertainty Reading questions/comments? Utility and risk attitude You can manage construction risks Risk management and insurances - Recommended

39 Decision Making Under Risk
Risk and Uncertainty Risk Preferences, Attitude and Premiums Examples of simple decision trees Decision trees for analysis Flexibility and real options

40 Multiple objective The student’s dilemma

41 Decision Making Under Risk
Risk and Uncertainty Risk Preferences, Attitude and Premiums Examples of simple decision trees Decision trees for analysis Flexibility and real options

42 Bidding What choices do we have?
How does the chance of winning vary with our bidding price? How does our profit vary with our bidding price if we win?

43 Example Bidding Decision Tree
Time

44 Choosing Elevator Count

45 Bidding Decision Tree with Stochastic Costs, Competing Bids

46 Selecting Desired Electrical Capacity

47 Decision Tree Example: Procurement Timing
Decisions Choice of order time (Order early, Order late) Events Arrival time (On time, early, late) Theft or damage (only if arrive early) Consequences: Cost Components: Delay cost, storage cost, cost of reorder (including delay)

48 Procurement Tree

49 Decision Making Under Risk
Risk and Uncertainty Risk Preferences, Attitude and Premiums Decision trees for representing uncertainty Decision trees for analysis Flexibility and real options

50 Analysis Using Decision Trees
Decision trees are a powerful analysis tool Example analytic techniques Strategy selection (Monte Carlo simulation) One-way and multi-way sensitivity analyses Value of information

51 Recall Competing Bid Tree

52 Monte Carlo simulation
Monte Carlo simulation randomly generates values for uncertain variables over and over to simulate a model. It's used with the variables that have a known range of values but an uncertain value for any particular time or event. For each uncertain variable, you define the possible values with a probability distribution. Distribution types include: A simulation calculates multiple scenarios of a model by repeatedly sampling values from the probability distributions Computer software tools can perform as many trials (or scenarios) as you want and allow to select the optimal strategy

53 Monetary Value of $6.75M Bid
This is histogram Streess that lumpsum amount Very few negative

54 Monetary Value of $7M Bid
Try to change scale

55 With Risk Preferences: 6.75M

56 With Risk Preferences: 7M

57 Larger Uncertainties in Cost (Monetary Value)

58 Large Uncertainties II (Monetary Values)
Ask what expect to see before showing this

59 With Risk Preferences for Large Uncertainties at lower bid

60 With Risk Preferences for Higher Bid

61 Optimal Strategy

62 Sensitivity Analysis I

63 Sensitivity Analysis II
Explain that regions at which different decisions are desirable

64 Decision Making Under Risk
Risk and Uncertainty Risk Preferences, Attitude and Premiums Decision trees for representing uncertainty Examples of simple decision trees Decision trees for analysis Flexibility and real options

65 Flexibility and Real Options
Flexibility is providing additional choices Flexibility typically has Value by acting as a way to lessen the negative impacts of uncertainty Cost Delaying decision Extra time Cost to pay for extra “fat” to allow for flexibility

66 Ways to Ensure of Flexibility in Construction
Alternative Delivery Clear spanning (to allow movable walls) Extra utility conduits (electricity, phone,…) Larger footings & columns Broader foundation Alternative heating/electrical Contingent plans for Value engineering Geotechnical conditions Procurement strategy Additional elevator Larger electrical panels Property for expansion Sequential construction Wiring to rooms

67 Illustration of Flexibility

68 Illustration of Flexibility: Selection of Elevator Count
More sophisticated model taking into account Initial costs Repair costs Loss due to lost conveyance

69 Sensitivity Analysis

70 Outcome

71 Strategy Selection

72 Adaptive Strategies An adaptive strategy is one that changes the course of action based on what is observed – i.e. one that has flexibility Rather than planning statically up front, explicitly plan to adapt as events unfold Typically we delay a decision into the future

73 Real Options Real Options theory provides a means of estimating financial value of flexibility E.g. option to abandon a plant, expand bldg Key insight: NPV does not work well with uncertain costs/revenues E.g. difficult to model option of abandoning invest. Model events using stochastic diff. equations Numerical or analytic solutions Can derive from decision-tree based framework

74 Example: Structural Form Flexibility
Hotel initially aimed at the low-end

75 Considerations Tradeoffs Frequently retrofitting $ > up-front $
Short-term speed and flexibility Overlapping design & construction and different construction activities limits changes Short-term cost and flexibility E.g. value engineering away flexibility Selection of low bidder Late decisions can mean greater costs NB: both budget & schedule may ultimately be better off w/greater flexibility! Frequently retrofitting $ > up-front $

76 Decision Making Under Risk
Risk and Uncertainty Risk Preferences, Attitude and Premiums Decision trees for representing uncertainty Examples of simple decision trees Decision trees for analysis Flexibility and real options

77 Readings Required Recommended: More information:
Utility and risk attitude – Stellar Readings section Get prepared for next class: You can manage construction risks – Stellar On-line textbook, from 2.4 to 2.12 Recommended: Meredith Textbook, Chapter 4 Prj Organization Risk management and insurances – Stellar

78 Risk - MIT libraries Haimes, Risk modeling, assessment, and management
Mun, Applied risk analysis : moving beyond uncertainty Flyvbjerg, Mega-projects and risk Chapman, Managing project risk and uncertainty : a constructively simple approach to decision making Bedford, Probabilistic risk analysis: foundations and methods … and a lot more!


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