Chapter 12 Risk Attitude and Utility Theory Utility Theory Maximize Expected Utility Motivation Rescale all values to between 0 and 1 based on risk attitude Certainty Equivalent Manage Risk – Utility Theory explains Insurance Partnership Risk Aversion assessment Standard function with parameters Direct assessment Problems with assessment Critique Chapter 12 Utility Theory: Paradox and Prospect Theory Chelst & Canbolat Value Added Decision Making 03/06/12 1 Utility Theory - Overview Incorporates decision-maker’s risk attitude Value of alternatives cannot be captured by E(X) because risk attitude Certainty Equivalent (CE): The payoff amount we would accept in lieu of under-going the uncertain situation, taking a gamble. Risk Premium: A situation’s risk premium (RP) is the difference between expected payoff (EP) and certainty equivalent (CE) Risk Aversion: CE < E(X) Concave function Profit – prefer sure profit that is less than E(X) of a profit gamble Cost – prefer sure cost that is higher than E(Y) of a loss gamble Risk Prone: CE > E(X) Try for more money than average With high guaranteed minimum, may be will to try for home run even if offered a value somewhat higher than the expected value Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 2 TV show “Deal or No Deal” – Activate WEB GAME Game Description and Risk Attitude Chapter 12 Game starts with 26 suitcases, each with a dollar value ranging from $0.01 to $1M Contestant picks one case as his to be opened at the end, and selects 6 cases to be opened immediately. As they are opened, their stored dollar value is deleted from the list. After opening these six cases, the player is offered a sure amount or the option to keep playing. At each the step the number of boxes to open at this stage decreases until only one at a time is opened each time. For example, I played the game until there were 3 unopened boxes left ($25, $50,000, and $1,000,000). One of these boxes I had selected as my box. The offer was for $220,000.This is much less than the expected value E(X) = (1/3)(25)+ (1/3)((50,000) + (1/3)(1,000,000) = (1/3) (1,000,025) = $350,008 If you prefer to take less than the expected value risk averse Chelst & Canbolat Value Added Decision Making 03/06/12 3 Simple gamble (lottery) – Two Outcomes Two boxes are left: $10,000 and $20,000. You have a 50–50 chance of winning $10,000 or $20,000 depending upon what is in your selected box. E(X) = $15,000 Would you accept an offer of $12,000 or continue Yes __ or No __ Would you accept an offer of $14,500 or continue Yes __ or No __ What is the minimum you would accept to stop the game? ___ this is Certainty Equivalent (CE) of the gamble If the CE is less than the expected value, you are a risk averse. Risk Premium is the difference between your CE and the expected value Assume you would accept $12,500 Risk Premium = E(X) – CE = $15,000 - $12,500 = $2,500 If the CE is more than the expected value, you are a risk prone. Gamble is a set of uncertain outcomes with probabilities Not necessarily just 2 outcomes All outcomes may not have the same probability. Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 4 Expected Value is Inadequate Generally Risk Averse Extremely Rare Catastrophic Events Law of averages no help for individual Motivates insurance industry Companies may self-insure up to extreme costs Can tolerate moderate risks that are not devastating Deductible on insurance Large investments relative to size of company Cannot afford the loss Has need for certain profit more than high upside potential sell development rights Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 5 Determine function U(X) U(X) function may be determined Select from standard functional forms – exponential or logarithmic and estimate parameters from questions Brute force graphing of the results of series of Certainty Equivalent responses to gambles Assume exponential U(X) = 1-e(-x/15000) U(20,000) = 1-e(-20000/15000) = .7364 Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 6 Calculate Expected Utility E(U(X)) and Not E(X) Assume exponential utility function for this example (0.5) $10,000 E(X) = 0.5($10000) + 0.5($20000) = $12,500 (0.5) $20,000 Assume U(X) = 1-e(-x/15000) U(10,000) = 1-e(-10000/15000) = 0.4866 U(20,000) = 1-e(-20000/15000) = 0.7364 E(U(X)) = 0.5(0.487) + 0.5(0.736) = 0.6115 invert exponential function CE(0.6115) = $14,182 $14,250 would be preferred to gamble $14,000 would not be preferred Chapter 12 Chelst & Canbolat Value Added Decision Making (0.5) 0.4866 0.7364 (0.5) 03/06/12 7 Invert function U(X) U-1(X) 0.6115 = 1-e(-x/15000) e(-x/15000) = ln of both sides (-X/15000) = ln(0.3885) = -0.9455 X = 15000 (0.9455) = 14,182 CE of 50-50 gamble of 10,000 and 20,000 is $14,182 Risk Chapter 12 1- 0.6115 = 0.3885 Premium = $15,000 - $14,182 = $818 Chelst & Canbolat Value Added Decision Making 03/06/12 8 Risk Aversion CONCAVE for Negative (Cost) Prefer to PAY More than expected value to be sure Cost does not get too large. 50-50 COST Gamble $90,000 or $10,000 => prefer sure $60,000 cost Basis for Insurance Industry CONCAVE for Maximization (Profit) Prefer to EARN less than expected value to be sure of earning at least that profit. 50-50 PROFIT Gamble $90,000 or $10,000 ===> would prefer sure $40,000 profit to the gamble. Basis for Selling off bank Debts such as mortgages Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 9 Risk Aversion – Concave Curve Profit Cost Risk Aversion - Cost 1.2 1.2 1 1 0.8 0.8 0.6 Series1 Utility Utility Risk Aversion - Profit 0.6 0.4 0.4 0.2 0.2 0 0 20000 40000 60000 80000 0 100000 -100000 Profit -80000 -60000 -40000 -20000 0 Cost 0.5 for $10,000 or 0.5 for $90,000 E(X) = $50,000 Accept $40,000 = CE U(40000)=.5 Risk Premium $10,000 Chapter 12 Utiltiy 0.5 for -$10,000 or 0.5 for -$90,000 E(X) = -$50,000 Accept -$60,000 = CE U(60000)=.5 Risk Premium $10,000 Chelst & Canbolat Value Added Decision Making 03/06/12 10 Activity – Risk Aversion Pay to avoid loss ___________________________________________ ___________________________________________ Accept less profit but be sure (or more certain) of profit ___________________________________________ ___________________________________________ Other Examples ___________________________________________ ___________________________________________ ___________________________________________ ___________________________________________ Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 11 Utility Function Assessment Brute Force Series of 3 lotteries Obtain Certainty Equivalent of utility values of .25, .5, & .75 Extrapolate over the range of 0 to 1. Create your own utility function for $0M to $10M set U(min) = 0 & U(max) = 1 set U(0) = 0 & U(10) = 1 Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 12 Decision tree Boss Controls automation investment Need utility function for four values (0.8, 1.9, 8.5, 10) 40.0% 9.9 Take Rate 5.86 60.0% 50% Take 16.5 0 1.9 40.0% 13.8 Take Rate 6.32 60.0% 50% Take 23 0.4 0.8 30% Take FALSE Low Automation Investment -8 0 8.5 How Much 6.32 30% Take High Chapter 12 TRUE -13 Chelst & Canbolat Value Added Decision Making 0.6 10 03/06/12 13 Certainty equivalents (0.5) XL ≈ CE50 (0.5) XH (0.5) XL ≈ CE25 (0.5) (0.5) CE50 XH ≈ CE75 (0.5) Chapter 12 CE50 Chelst & Canbolat Value Added Decision Making 03/06/12 14 BC automation investment certainty equivalent for 0.50, 0.25, and 0.75 utility (0.5) 0 (0.5) (0.5) (0.5) (0.5) (0.5) Chapter 12 10 ≈ CE50 = 3.6 0 ≈ CE25 = 1.6 3.6 10 ≈ CE75 = 6.2 3.6 Chelst & Canbolat Value Added Decision Making 03/06/12 15 Utility assessment for BC automation investment example 1 Utility Score 0.8 0.6 0.4 0.2 0 0 2 4 Dollars 6 8 10 Value 0 0.8 1.6 1.9 3.6 6.2 8.5 10 Utility 0 0.13 0.25 0.29 0.5 0.75 0.90 1 Table 12-4: Utility scores for BC automation investment Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 16 Decision tree for BC automation investment using utility function FALSE 40% 0 0.13 60% 0 1.0 40% 0.29 0.4 0.29 60% 0.9 0.6 0.90 30% Take Rate 0.13 Take Rate 0.652 High 50% Take Rate 1.0 Automation Investment Decision 0.657 30% Take Rate TRUE Take Rate 0.657 Low 50% Take Rate CE: $5.142 (0.652) vs. $5.196 million (0.657) Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 17 Utility Function: Simplify Interview Goal: simplify interview process One question for each parameter Exponential U(x) = 1 – exp(-x/R) Constant Risk Aversion Implies that the magnitude of cash on hand does not affect attitude towards Risk R = Risk Tolerance R = Sum of Money about which you are indifferent between a 50-50 chance of gaining the whole sum, R and losing the half sum, R/2 Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 18 Constant Risk Aversion Risk Premium is Constant R=35 Chapter 12 U(X) = 1 – exp(-x/35) 50-50 Gamble Expected Certainty Risk Between ($) Value Equivalent Premium 10,40 25 21.88 3.12 20,50 30,60 40,70 35 45 55 31.88 41.88 51.88 3.12 3.12 3.12 Chelst & Canbolat Value Added Decision Making 03/06/12 19 Determine R = Risk Tolerance 50- 50 gamble to determine R Personal Chapter 12 Win Lose $20 $200 $2,000 $20,000 $10 $100 $1,000 $10,000 Chelst & Canbolat Value Added Decision Making Would take Gamble Y/N 03/06/12 20 Determine R = Risk Tolerance 50- 50 gamble to determine R Corporate Chapter 12 Win Lose $20,000 $200,000 $2,000,000 $20,000,000 $10,000 $100,000 $1,000,000 $10,000,000 Chelst & Canbolat Value Added Decision Making Would Corp. Gamble Y/N 03/06/12 21 ENCO Project Selection An energy company will select one of two projects. If the company chooses Project A, it will undertake the development of a new power plant in one developing country. The company estimates that the investment cost will be $50 million and total revenue for five-year after the operation cost will be $80, $90, or $110 million. There is a 20% chance that the local government will take over the plant once it is finished due to some legal issues and just repay the original investment cost ($50 million). Project B also requires a $50 million investment. Total revenue for five-year after the operation cost will be $66, $80, or $90 million. In this second country, there is no chance that the government will take over this project when it is completed. Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 22 Maximize expected value Decision tree for ENCO project selection 0.2 20.0% Yes 0 50 TRUE Project A Government Take Project? 34.4 -50 30.0% Low 80 43 0 40.0% Medium 90 30.0% High 110 Project 30 Revenue 80.0% No 0.24 0.32 40 0.24 60 Project Decision 34.4 Low Project B FALSE 0 66 16 40.0% 0 80 30 30.0% 0 90 40 Revenue 28.8 -50 Medium High Chapter 12 30.0% Chelst & Canbolat Value Added Decision Making 03/06/12 23 Figure 12.11: Cumulative risk profile for ENCO project selection Redraw diagram without student version 1 Cumulative Probability 0.8 0.6 Project A Project B 0.4 0.2 Chapter 12 Chelst & Canbolat Value Added Decision Making 70 60 50 40 30 20 10 0 -10 0 03/06/12 24 A utility score was calculated for each value. R= $30 million EU(Project A) = 0*20% + (0.632*30%+0.736*40%+0.865*30%)*80% = 0.595 EU(Project B) = 0.413*30%+0.632*40%+0.736*30% = 0.598 Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 25 Decision tree for ENCO: using expected utility Yes Project A FALSE -50 20.0% 0 0.000 50 Government Take Project? 0.595 No Project 80.0% 0 Revenue 0.744 40.0% Medium 90 30.0% High 110 0 0.632 0 0.736 0 0.865 Project Decision 0.598 Project B Low TRUE -50 Revenue 0.598 Medium High Chapter 12 30.0% 80 Low 30.0% 66 0.3 0.413 40.0% 80 30.0% 90 0.4 0.632 0.3 0.736 Chelst & Canbolat Value Added Decision Making 03/06/12 26 Impact of risk tolerance on certainty equivalent Certainty Equivalent 35.00 30.00 25.00 20.00 15.00 Project A 10.00 Project B 5.00 0.00 1 10 20 30 40 50 60 Risk Tolerance Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 27 Risk Sharing Strategies Buy insurance Partnerships Example: Transmission plant by GM and Ford Joint ventures with foreign companies Diversification Diversification with independent investments Example: Dual sourcing, investment in different stocks Diversification with dependent investments (Hedging) Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 28 Risk Sharing through Buy Insurance: Project Selection Chapter 12 Buy insurance against a government takeover of project A. $4 million premium the company will receive a $10 million payment if the government takes the project. Add new decision branch to tree as part of Project A. (top of next tree) Chelst & Canbolat Value Added Decision Making 03/06/12 29 ENCO: insurance reporting expected value 20.0% Yes FALSE Buy Insurance -4 0 6 60 Government Take Project? 32.400 30.0% 80 Revenue 39.000 Medium 40.0% 90 Low 80.0% 0 No TRUE Project A -50 High Insurance Decicion 34.400 20.0% Yes TRUE Do Not Buy 0 50 Government Take Project? 34.400 30.0% 110 80.0% 0 Project Insurance 30.0% 80 Revenue 43.000 Medium40.0% 90 0.24 30 30.0% 110 0.24 60 High Project Decision 34.400 Low Project B FALSE -50 Revenue 28.800 Medium High Chapter 12 30.0% 66 0 16 40.0% 80 30.0% 0 30 0 40 Chelst & Canbolat 90 Value Added Decision Making 0 36 0 56 0.2 0 Low No 0 26 03/06/12 0.32 40 30 ENCO : insurance option reporting CE TRUE Buy Insurance -4 Insurance Decision 27.630 Project A TRUE -50 FALSE Do Not Buy 0 Project Decision 27.630 20.0% 0.2 60 6 Government Take Project? 27.630 30.0% Low 80 80.0% Revenue No 0 36.830 Medium 40% 90 Yes High 30.0% 110 20.0% 0 50 0 Government Take Project? 27.107 30.0% Low 80 80.0% Revenue No 0 40.83040.0% Medium 90 High Project B Chapter 12 FALSE -50 0.32 36 0.24 56 Yes Project Insurance 30.0% 66 Revenue 27.322 40.0% Medium 80 30.0% High Chelst & Canbolat 90 Value Added Decision Making Low 0.24 26 0 16 0 30 0 40 30.0% 110 03/06/12 0 30 0 40 0 60 31 Decision Tree for Insurance company Tree Not in Textbook Yes TRUE Sell 20.0% 0.2 -10 -6 Government Take Project? 4 2 80.0% No 0 Insurance Company 0.8 4 Decision 2 Do Not Sell Chapter 12 FALSE 0 0 0 Chelst & Canbolat Value Added Decision Making 03/06/12 32 Share Risk through Partnership Concept: Commit to only a percentage of the cost (liability) and accrue the equivalent percentage of revenue Common amongst insurance companies to reinsure and share risk of catastrophic event – Lloyd’s of London Decision Tree Method – reduce costs and revenues proportionate to share and calculate new utility scores. Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 33 Share Risk through Partnership: Project Selection Chapter 12 Outside investor shares 50% of cost and benefit of each project. By sharing the investment, the company can now be involved in more projects. Let’s evaluate a 50% share. As a result the company can invest in BOTH A and B. Chelst & Canbolat Value Added Decision Making 03/06/12 34 ENCO with 50% partnership reporting expected profit Government takes away project A? TRUE 34.400 -50 + Project Decision 34.400 FALSE Revenue Project B + 28.800 -50 30.0% Low 33 20.0% Revenue from B Yes 14.400 25 40.0% Medium 40 30.0% High 45 FALSE Government takes away project A? 50% of Both Projects 31.600 -50 Project A Project - Diversification 0 8 0 15 0 20 30.0% 33 Revenue from B 29.400 40.0% Medium 40 30.0% High 45 Low Low No Chapter 12 80.0% 0 30.0% 40 0 23 0 30 0 35 Revenue from A 35.900 40.0% Revenue from B Medium 34.400 45 + Revenue from B 30.0% High 44.400 55 + Chelst & Canbolat Value Added Decision Making 03/06/12 35 ENCO decision tree with partnership option reporting certainty equivalent Project A Project - Diversification FALSE -50 Government Take Project? + 27.107 FALSE -50 + Project Decision 29.450 Project B Revenue 27.322 0.06 8 30.0% 33 Revenue from B 20.0% Yes 14.032 25 Medium 40.0% 40 30.0% High 45 Government Take Project A? 29.450 Low 50% of Both Projects TRUE -50 0.08 15 0.06 20 30.0% 33 Revenue from B 29.032 40.0% Medium 40 30.0% High 45 Low Low No Chapter 12 80.0% 0 Chelst & Canbolat Value Added Decision Making 30.0% 40 Revenue from A 34.966 Medium 40.0% + 45 30.0% High + 55 0.072 23 0.096 30 0.072 35 Revenue from B 34.032 Revenue from B 44.032 03/06/12 36 Optimize PERCENT Share of Project Can optimize based on risk attitude Percent share of option A Percent share of option B Different companies with different risk attitudes will have different optimum preferences Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 37 Phillips Petroleum and Onshore US Oil Exploration Prospect Ranking: R equal to $25 million Expected Value Basis Prospect Rank EV 100% share Certainty Equivalent Basis Rank Optimal Share Certainty Equivalent South Louisiana 1 18.6 8 12.5% 0.6 Norphlet 2 16.5 6 12.5% 0.8 Wilcox 3 11.8 5 25% 0.8 Frio 4 10.8 7 12.5% 0.7 Vicksburg 5 4.0 4 75% 1.0 Yegua Deep 6 3.0 3 100% 1.0 Smackover 7 2.5 1 100% 1.8 Yegua Shallow 8 2.2 2 100% 1.1 Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 38 Following two slides not in the textbook Impacts of the target setting on the risk attitude Consistent with prospect theory Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 39 Risk Attitude and Targets Component Cost Target $46 – Goal: Minimize Cost You are near completion on a design and are almost certain that you will be able to reach the variable cost target of $46. A suggestion comes along that by changing materials the component should be easier to manufacture with the cost dropping to $40 per part. However, time is short and there is a concern that without proper testing of Design for Manufacture the change could, in fact, increase the cost to $47 per component and miss the target. Would you make the change assuming the two outcomes were equally likely? .5 $46 OR .5 Chapter 12 $47 Chelst & Canbolat Value Added Decision Making $40 03/06/12 40 Risk Attitude and Targets Component Cost Target $40 You are near completion on a design and are almost certain that you will NOT be able to reach the variable cost target of $40 and that the part will cost $42. A suggestion comes along that by changing materials the part should be easier to manufacture with the cost dropping to $40 per part. However, time is short and there is a concern that without proper testing of Design for Manufacture the change could, in fact, increase the cost to $47 per part and miss the target. Would you make the change assuming the two outcomes were equally likely? .5 $42 OR .5 Chapter 12 $47 Chelst & Canbolat Value Added Decision Making $40 03/06/12 41 Problems With Carrying Out Risk Aversion Assessment in Real-World Managers are uncomfortable with this abstract concept Managers are inconsistent -- Prefer ranges for CE and not specific values People are inconsistent risk prone for small values ( i.e. will buy lottery tickets) risk averse for large values (i.e. buy insurance) May be risk prone if values are negative but risk averse if all values are positive and vice versa Attitudes towards risk are influenced by artificial targets Target secure – take no gamble to improve Target at risk – take extreme gambles to reach target Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 42 Risk Assessment In Practice (Done Less than 10% of the time) Howard Rule of Thumb for R in major decisions: R = 6.4% of sales or 1.25 Net Income – Your company value? Example: R = $1 Billion dollar investment or purchase decision for a company with over $15 Billion in sales. First carry out analysis without Risk Aversion Display Comparative Risk Profiles and discuss Insert exponential function & determine whether or not the optimal solution is Sensitive to Risk Tolerance Value within a realistic range for your company. If optimal decision can change within a reasonable range of R then assess actual utility function. Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 43 Assumptions of Utility Theory Expectation: U(x1,p1;…;xn,pn) = p1u(x1)+…+pnu(xn) Asset Integration: The domain of the utility function is final states (which include one’s asset position) rather than gains or losses. Risk Aversion: u is concave (u’’< 0) Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 44 Critique of Utility Theory Expectation Assumption - Allais paradox Problem 1: Choose between A: $1 Million with certainty Problem 2: Choose between X: $1 Million with probability 0.11 0 with probability 0.89 Chapter 12 B: $1 Million with probability 0.89 $5 Million with probability 0.10 0 with probability 0.01 Y: $5 Million with probability 0.10 0 with probability 0.90 Chelst & Canbolat Value Added Decision Making 03/06/12 45 Critique of Utility Theory- Actual preferences Expectation Assumption - Allais paradox Problem 1: 82% choose A A: $1 Million with certainty B: $1 Million with probability 0.89 $5 Million with probability 0.10 0 with probability 0.01 Problem 2: 83% Choose Y X: $1 Million with probability 0.11 0 with probability 0.89 Y: $5 Million with probability 0.10 0 with probability 0.90 Conclusion: People overweight “certain” outcomes more than merely probable outcomes. Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 46 Utility Function Stability and Accuracy Affected by mood Quality of life QOL Assessment of QOL living with serious disease. Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 47 Prospect Theory (Kahneman and Tversky) Example not in textbook Value Function ◦ Concave for gains and Convex for losses; ◦ Steeper for losses than gains (Loss Aversion) v(x) 1200 800 400 0 -1200 -800 -400-400 0 v(x) 400 800 1200 -800 -1200 Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 48 Prospect Theory (Kahneman and Tversky) Example not in textbook Weighting Function (The impact of events on desirability of prospects, not merely the likelihood of events) ◦ Overweight certainty and small probabilities; ◦ Underweight moderate and high probabilities; 1 0.8 0.6 w+(p) w-(p) 0.4 0.2 0 0 Chapter 12 0.2 0.4 0.6 0.8 Chelst & Canbolat Value Added Decision Making 1 03/06/12 49 Prospect Theory (Kahneman and Tversky) Example not in textbook Chapter 12 Fourfold risk attitude: Small Probabilities Moderate or high probabilities Gains risk seeking risk averse Losses risk averse risk seeking Chelst & Canbolat Value Added Decision Making 03/06/12 50 Remember The Goal of Analysis Update Intuition of Decision Maker Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 51 Where are we headed next? Analytic Tools completed! YEAH! No more new software! Data input: forecasting biases Structured expert interview Decision making biases awareness Ethics Decisions Negotiations Strategic Decisions & Scenario Planning Final Projects Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 52 TREES-A Decision-Maker's Lament I think that I shall never see A decision as complex as that treeA tree with roots in ancient days (At least as old as Reverend Bayes); A tree with flowers in its tresses (Each flower made of blooming guesses); A tree with utiles at its tips (Values gleaned from puzzled lips); A tree with trunk all gnarled and twisted With axioms by Savage listed; A tree with stems so deeply nested Intuition's completely bested; A tree with branches sprouting branches And nodes declaring what the chance is; A tree with branches in a tangle Impenetrable from any angle; Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 53 TREES-A Decision-Maker's Lament A tree that tried to tell us "should" Although its essence was but "would"; A tree that did decision hold back 'Til calculation had it rolled back. Decisions are reached by fools like me, But it took a consultant to make that tree. Michael H. Rothkopf with apologies to Joyce Kilmer and to competent, conscientious decision analysts everywhere Operations Research Vol. 28, No. 1, January-February 1980 Chapter 12 Chelst & Canbolat Value Added Decision Making 03/06/12 54