Operations and Supply Chain Management
Operations Management: Sustainability and Supply Chain Management
Week 5
Module A: Decision-Making Tools
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
If this PowerPoint presentation contains mathematical equations, you may need to check that your computer has the following installed:
1) MathType Plugin
2) Math Player (free versions available)
3) NVDA Reader (free versions available)
1
Learning Objectives
1 Create a simple decision tree
2 Build a decision table
3 Explain when to use three types of decision-making environments
4 Calculate an expected monetary value (E M V)
5 Compute the expected value of perfect information (E V P I)
6 Evaluate the nodes in a decision tree
7 Create a decision tree with sequential decisions
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
2
The Decision Process in Operations
Clearly define the problem and the factors that influence it
Develop specific and measurable objectives
Develop a model
Evaluate each alternative solution
Select the best alternative
Implement the decision and set a timetable for completion
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
3
Fundamentals of Decision Making
Symbols used in a decision tree:
– Decision node from which one of several alternatives may be selected.
– A state-of-nature node out of which one state of nature will occur
Terms:
Alternative – a course of action or strategy that may be chosen by the decision maker
State of nature – an occurrence or a situation over which the decision maker has little or no control
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
4
Decision Tree Example
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
5
Decision Table Example
Decision Table with Conditional Values for
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
6
Decision-Making Environments
Three types
Decision making under uncertainty
Complete uncertainty as to which state of nature may occur
Cannot assess probabilities for each possible outcome
Decision making under risk
Several states of nature may occur
Each has a probability of occurring
Decision making under certainty
State of nature is known
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
7
Uncertainty
| Maximax | Maximin | Equally likely |
| Find the alternative that maximizes the maximum outcome for every alternative | Find the alternative that maximizes the minimum outcome for every alternative | Find the alternative with the highest average outcome |
| Pick the outcome with the maximum number | Pick the outcome with the minimum number | Pick the outcome with the maximum number |
| Highest possible gain | Least possible loss | Assumes each state of nature is equally likely to occur |
| This has been called an optimistic decision criteria | This has been called a pessimistic decision criteria |
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
8
Type 1: Decision Table Under Uncertainty
Maximax choice is to construct a large plant
Maximin choice is to do nothing
Equally likely choice is to construct a small plant
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
9
Type 2: Decision Making Under Risk
Each possible state of nature has an assumed probability
States of nature are mutually exclusive
Probabilities must sum to 1
Determine the expected monetary value (E M V) for each alternative
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
10
Expected Monetary Value
| EMV (Alternative i) | = | (Payoff of 1st state of nature) × (Probability of 1st state of nature) |
| Blank | + | (Payoff of 2nd state of nature) × (Probability of 2nd state of nature) |
| Blank | +… + | (Payoff of last state of nature) × (Probability of last state of nature) |
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
11
Decision Table Example
Best Option
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
12
Type 3: Decision Making Under Certainty
| Expected value with perfect information (EVwPI) | = | (Best outcome or consequence for 1st state of nature) × (Probability of 1st state of nature) |
| Blank | + | Best outcome for 2nd state of nature) × (Probability of 2nd state of nature) |
| Blank | +… + | Best outcome for last state of nature) × (Probability of last state of nature) |
Is the cost of perfect information worth it?
Determine the expected value of perfect information (E V P I)
EVPI = the payoff under certainty - the payoff under risk
EVPI = expected value with perfect information – Maximum EMV
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
13
E V P I Example
The best outcome for the state of nature "favorable market" is
"build a large facility" with a payoff of $200,000.
The best outcome for "unfavorable“ is
"do nothing" with a payoff of $0.
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
14
The maximum E M V is $52,000, which is the expected outcome without perfect information. Thus:
The most the company should pay for perfect information is
$68,000
Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved
15