Introduction to Decision Analysis • Decision analysis studies the process of making difficult decisions • The objective is to update, model, and document the intuition of managers • A structured approach to decision making is especially critical in group decision making • Key importance in the case of resource decisions (operations strategy) MGT3303 Michel Leseure Why are decisions difficult? • Complexity – Simply keeping all the issues in mind at one time is nearly imposible • Uncertainty – Making a decision is especially difficult when you are not sure about one decision variable’s state • Multiple objectives • Different perspectives lead to different conclusions MGT3303 Michel Leseure Example • Winter of 1985: – The Oregon Department of Agriculture (ODA) faced an infestation of gypsy moth in Lane County in Western Oregon – Forest industry representative call for an aggressive eradication campaign MGT3303 Michel Leseure Alternatives • Use BT, a bacterial insecticide – target specific – ecologically safe – reasonably effective • Use Orthene, a chemical spray – registered as acceptable for home garden use – questions about its ultimate ecological effects – possible danger to humans • Possible to use both MGT3303 Michel Leseure Opinions • Forestry officials: – Argue Orthene is more potent and is necessary to ensure eradication • Environmentalists: – Orthene potentially too dangerous • Others – Already too late anyway • Others... – Still time but decision/implementation has to be made now MGT3303 Michel Leseure Subjective Judgments • In decisional contexts such as the one faced by ODA – objective data is lacking – a procedure determining an « optimal » decision derived from objective data is of little use... – personal statements about uncertainty and value become important inputs (no choice...) – Discovering and finalizing these judgments is a key issue in decision analysis – Instead of criticizing them, we will learn how to better assess and use them MGT3303 Michel Leseure The Decision Analysis Process • Identify the decision situation and understand objectives • Identify alternatives • Decompose and model the problem – model of problem structure – model of uncertainty – model of preferences • • • • Choose the best alternative Sensitivity analysis Is further analysis needed? yes/no? Implement the chosen alternative MGT3303 Michel Leseure Requisite Decision Models • A model can be considered requisite only when no new intuitions emerge about the problem • or when it contains everything that is essential for solving the problem MGT3303 Michel Leseure Elements of a Decision Problem • • • • Values and objectives Decisions to make Uncertain events Consequences MGT3303 Michel Leseure Values and Objectives • Value: used in its general sense « things that matter to you » • Objective: Specific thing that you want to achieve • The set of objectives taken up together make up the values • Values are the reason for making the decision in the first place • They define the decision context MGT3303 Michel Leseure Objectives for Boeing’s Supercomputer Supercomputer Objectives Cost Performance Five-year costs Cost of improved performance Speed Throughput Memory Size Disk Size On-site performance User Needs Installation date Roll in/Roll out Ease of Use Software compatibility Mean time between failures Operational Needs Square footage Water cooling Operator tools Telecommuni-cations Vendor support Management Issue Vendor Health US Ownership Commitment to supercomputer MGT3303 Michel Leseure Decision to Make • Given a decisional context, one (or several) decision(s) has to be made • In some cases, several decisions may have to be made in a sequence Time Decision 1 Decision 2 Decision 3 MGT3303 Michel Leseure Uncertain Events – Uncertain events are either linked to chance or are linked to a probability distribution – Uncertain events have outcome – It is important to position uncertain events appropriately between decisions Decision 1 Decision 2 Time Decision 3 MGT3303 Michel Leseure Consequences • After the last decision has been made and the last uncertain event has been resolved, the decision maker’s fate is finally determined Time Decision 1 Decision 2 Decision 3 Consequence MGT3303 Michel Leseure Example Weather for Cleanup Weather Accident Cost Location Environmental Damage Cause Policy Decision Time Accident Management Decisions Consequence: Cost $ Environmental damage PR damage MGT3303 Michel Leseure Making Choices • Decision Trees • Example: Texaco vs. Pennzoil • Decision trees and expected value – certainty equivalent MGT3303 Michel Leseure Decision Trees • Decision trees are a graphical representation of a decision problem Venture succeeds Invest Large return Funds lost Venture fails Do not invest Typical return earned on less risky investment MGT3303 Michel Leseure Decision Tree Evacuate Safety Cost Safe High Danger Low Safe Low Storm hits Miami Forecast Stay Storm misses Miami MGT3303 Michel Leseure Cash Flows and Probabilities • To each branch of the tree, we can attach – a probability – and/or, a cash flow – or any measure replacing monetary values for a specific problem MGT3303 Michel Leseure Case Study: Texaco vs. Pennzoil • In early 1984, Pennzoil and Getty Oil agreed to the terms of a merger • Before the signature of the formal agreement, Texaco offered Getty a substantially better price , and Gordon Getty (majority stockholder) defected on Pennzoil and sold to Texaco MGT3303 Michel Leseure Case Study: Texaco vs. Pennzoil • Pennzoil felt this was unfair practice and filed a lawsuit against Texaco, alleging that Texaco had interfered illegally in the the Pennzoil-Getty negotiations • Pennzoil won the case in late 1985 and was awarded $11.1 billion – the largest settlement in the US at this point in time • Texaco appealed and the settlement was reduced by $2 billion – but interest and penalty got the amount back to $10.3 billion MGT3303 Michel Leseure Case Study: Texaco vs. Pennzoil • Kinnear, Texaco’s CEO, announced that Texaco would file for bankruptcy if Pennzoil obtained court permission to secure the judgment by filing liens against Texaco’s assets • Kinnear promised to fight the case all the way to the Supreme Court MGT3303 Michel Leseure Texaco’s Offer • In April 1987, just before Pennzoil started filing liens, Texaco offered to pay Pennzoil $2billion to settle the entire case • Liedtke, chairman of Pennzoil, announced that his advisors estimated that a settlement of 3-5 billions would be fair What should Liedtke do? MGT3303 Michel Leseure Decision Tree Settlement Amount ($billion) Accepts $2 billion 2 Texaco accepts $5 billion Counteroffer $5 billion Texaco counteroffers $3 billion Texaco refuses counteroffer Final Court Decision Final Court Decision Refuse Accepts $3 billion 5 10.3 5 0 10.3 5 0 3 MGT3303 Michel Leseure Subjective Probabilities • In the decision tree, we are missing probability estimates of the each event • For this lecture, we will take these probability values for granted MGT3303 Michel Leseure Decision Tree Accepts $2 billion Settlement Amount ($billion) 2 Texaco accepts $5 billion (0.17) Counteroffer $5 billion (0.33) Texaco counteroffers $3 billion 5 (0.2) Texaco refuses counteroffer (0.50) 10.3 5 (0.3) 0 (0.2)10.3 (0.5) 5 (0.3) 0 Final Court Decision (0.5) Final Court Decision Refuse Accepts $3 billion 3 MGT3303 Michel Leseure Expected Monetary Value • Computing an expected monetary value is a way of selecting among risky alternative • Computing expected values bring the problem back to a « certainty equivalent » • What is the expected value of the court judgment? MGT3303 Michel Leseure Expected Value of the Court Judgment • EV = 0.2 * 10.3 + 0.5 * 5 + 0.3 * 0 • EV = $ 4.56 billion (0.2) Final Court Decision (0.5) (0.3) 10.3 5 0 It is possible to reduce the tree with this certainty equivalent MGT3303 Michel Leseure Reduced Tree Accepts $2 billion Texaco accepts $5 billion 2 5 (0.17) Counteroffer $5 billion (0.33) Texaco counteroffers $3 billion Eliminated Texaco refuses counteroffer 4.56 (0.50) Refuse Accepts $3 billion 4.56 3 MGT3303 Michel Leseure Expected Monetary Value of the Counteroffer • What is the expected monetary value of Pennzoil $5 billion counter offer: • EV = P(Texaco accepts) * 5 + P(Texaco refuse) * 4.56 + P(Texaco counteroffers) * 4.56 • EV = 4.63 Liedtke should not accept the $2 billion offer, and should counter-offer $5 billion. If Texaco refuses, then the matter should be taken to court MGT3303 Michel Leseure Reducing the Decision Tree • In practice, we do not reduce the decision tree but report expected values on the nodes MGT3303 Michel Leseure Resolved Decision Tree Accepts $2 billion 2 Texaco accepts $5 billion Counteroffer $5 billion 4.63 (0.33) Texaco counteroffers $3 billion (0.17) 5 (0.2) Texaco 4.56 refuses counteroffer (0.50) 4.56 Refuse Final Court Decision (0.5) (0.3) (0.2) Final Court Decision Accepts $3 billion (0.5) (0.3) 10.3 5 0 10.3 5 0 3 MGT3303 Michel Leseure Suggested Homework • Problem S2-10, p. 70 • Problem S2-13, p. 71 MGT3303 Michel Leseure