Samuel E. Bodily
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GBUS 8900 Management Decision Models
Course Description | Schedule | Software Resources | Templates | References


Assignments
- Fall Late Week, 11:45-1:10 PM, Room 280.
In the first week we will begin to create models of dynamics that develop over time.

1.  Assignment for Creating a Dynamic Model

Reference: Background reading about influence diagrams is contained in Structuring Assumptions in Decision Making (UVA-QA-0499), page 1 thru top of page 8, and page 15 to end.

If you desire extra reading for the first four sessions of the course, or another slant on developing a model, see chapter 2 (and perhaps other chapters) of Management Science: The Art of Modeling With Spreadsheets, Second Edition, Powell, Stephen G., and Kenneth R. Baker, John Wiley and Sons, 2007, on reserve for the course in the Darden Library.

Prepare:  Internet Rapide (UVA-QA-0617)

Assignment Questions:

1.  What would be your recommendation on the basis of a single period?  Is it necessary to do more than a single period model?  Why?

2.  How would you structure a multi-period model?

- what is the performance measure (or value criterion) you wish to maximize?
- what are the decision variables?
- what are the core intermediate variables?  An influence diagram to draw the relationships among these core intermediate variables--if a variable is influenced by the previous value of a variable, label the influence arrow with PREVIOUS
- complete the influence diagram including relationships among all variables (decision variables, intermediate variables and the performance measure).  Do not let this get too complicated--a dozen variables should be plenty to capture the model. Use references to previous

3.  Prepare an Excel spreadsheet model on which to develop a multi-period recommendation (let's all take the model out 21 quarters for starters; at period 0 all 1 million customers are type A). Check that your influence diagram matches your model. 

4.  Use a guided trial and error search to find a reasonable recommendation. Your own trial and error search for the best plan will be sufficient, optimization is not necessary.  Spend your time on a spreadsheet model that captures the essential elements without being fancy.  AVOID SOLVER--YOUR MODEL IS NONLINEAR AND YOU'D NEED TO START IT AT A HUGE NUMBER OF STARTING POSITIONS TO GET ANY ASSURANCE OF A GLOBAL OPTIMUM. The adventurous may want to try using Optquest on their model (a User's Guide for Optquest is available in the course packet for class 12).

5.  Please submit your Excel file for Internet Rapide to me for use in class discussion no later than 8 a.m. on the day of class.   You are allowed to work together on this.
(Optional) You may care to include your influence diagram in an Excel worksheet in your workbook, or not.

Name your file so that the first three letters indicate the case (INT), the next 6 are the first six letters of your surname, and the next 6 are the first six letters of your given name. Thus the spreadsheet of the student Juan Zapata Tyme for Internet Rapide would be saved as:

INTTyme__Juan__.XLS .

If you work together concatenate all additional names to the file name, e.g. INTSurnamGivenm SurnamGivenm SurnamGivenm.  Submit your file to the course assignment drop box located at the MDM Course Folder using the instructions for uploading files that you will receive by email.

Objectives: 

Introduction to structuring spreadsheet relationships

§  Using influence diagrams

§  Building dynamic models

Alternate time horizons for decisions

§  Snapshot one-period

§  Short- a few periods

§  Long-term

Decision interactions and guided search

2.  Assignment for MNB One

Read: "Markov Brand-Switching Models," Section 13.1 of Management Spreadsheet Modeling and Analysis, by Rick Hesse, Irwin, Chicago, 1997.

Reference: The following link gives examples of Markov chains, including a weather example and a link to the underlying page-rank approach of Google, which is based essentially on a Markov process, where the states are url's on the internet.

http://en.wikipedia.org/wiki/Examples_of_Markov_chains

Prepare: MNB One Credit Card Portfolio (UVA-QA-0613)

Assignment Questions:

1.  What is the valuation of the portfolios based on current contribution?

2.  Which portfolio should Duguid recommend for purchase?

3.  What insight can a Markov model provide into the value of a customer:

     - Which would you prefer, a Current or a 30-Day Markus Nayman customer?  Why?

     - Compare the value of a randomly selected Sirtem customer with a Markus Nayman
     customer.  Why is one better than the other?

4.  How much should Duguid be willing to spend on the educational program?

5.  What are some situations where Markov processes would be appropriate to capture the dynamics of a system?

Use the spreadsheet MNB One.xls in your preparation. 

See the optional material in the course folder  (Interfaces Vol. 35, No. 5, Sept-Oct. 2005) with my highlights and notes:  Merrill Lynch used Monte Carlo simulation of a Markov process (where the states relate to client credit ratings) to save $4 billion dollars of liquidity.  Doing this in your finance job would make you a big hero. 

Objectives:

Introduction to Markov processes

§  Initial state distributions

§  Transition matrices

§  Payoffs

§  Steady-state probabilities

Initial states versus transition probabilities

§  Comparative value

§  Tradeoffs

Summary of dynamic models

3.  Assignment for Risk Preference Class

Read: pages 120-128 of "Risk Preference and Utility," (the first 9 pages of) chapter 9 of Quantitative Business Analysis: Text and Cases (QBA), by Bodily, Carraway, Frey, and Pfeifer.

Prior to this class:

Complete levels 1 and 2 of the Risk_Preference_Utility_Math quiz, located at
http://it.darden.virginia.edu/BTN/
You may need to self-register for the quiz using the register link on the main page. The quiz begins at level 1 (easiest problems) and you will work your way up in difficulty levels as you answer questions correctly. Correspondingly, missing questions will cause your difficulty level to drop. This is similar to the GMAT format.

Prepare:

1. Exercises 1 and 2 at the end of chapter 9, page 133.

2. (Optional) Assessing Your Own Utility to Compare Signup Bonuses (attached in hardcopy).  Use the spreadsheet Bonus Dollars.xls in your preparation.  This spreadsheet makes use of TreePlan, a spreadsheet add-in for decision tree analysis. The tree is already developed in Bonus Dollars.xls for you to use.  You need only enter your risk tolerance in the appropriate cell. 

Software Resource:

ASSESS is an Interactive Program for Utility Assessment from Philippe Delquié of Insead.  Click here to download <ASSESSinstall.zip>, a zip file containing ASSESS for Windows. After downloading, extract all files to a temporary folder and run Setup.exe. 

Assignment Questions:

While you can use a calculator or a spreadsheet to do exercises 1 and 2 at the end of the chapter, you may wish to use TreePlan to develop a decision tree.  Documentation for downloading and using TreePlan is in a PDF on the course folder (open Treeplan.xla with Excel to use it).  Note that to use a constant risk-averse utility function with Treeplan, you must choose "Use Exponential Utility" in the Options dialog box (which comes up in the dialog window in Excel when you hit CTRL+Shift+T), and you must place a risk tolerance number in a cell that has a range name RT.  In Excel, find Define Name on the Formula ribbon to create a range name.

After reading the chapter and preparing the exercises above, consider how risk preference should be used in practice in the corporation.

Objectives:

Introduction to risk preference

§  Certainty equivalent

§  Risk premium

§  Utility function

§  Expected utility captures it all

Using expected utility

§  in a decision tree

§  for insight about diversification.

4.  Assignment for Risk Preference Utility Exercises

Prepare:

1. Risk Preference Utility Caselets (UVA-QA-0703).  

Reference: 

1.  "Risk Preference and Utility," chapter 9 of QBA.

Read:  Deal or No Deal paper (to be distributed)

Assignment Questions:

1.  Make use of TreePlan to prepare caselets I and III. 
Note:  TreePlan can be used for Caselet III only if the expected utility calculation for each event branch is modified to use logarithmic utility.  Solver may be useful for question IIIc. What is the valuation of the portfolios based on current contribution?
 

2.  How much additional value would be gained in the "Deal or no Deal" game

     a.  from using expected utility?

     b.  from simply not being risk-seeking?

Suggest some business situations where you think additional value could be obtained by using expected utility.

   

Recommended prior to class session 4, especially if the use of expected utility for risk preference needs more clarity:

Complete levels 3 and 4 of the Risk_Preference_Utility_Math quiz on the Darden BusinessMath site. This is located at http://it.darden.virginia.edu/BTN/ .  A small portion (5%) of your grade is connected to completing the four levels by Class 12, September 23.

Objectives:

Applying risk preference

§  in TreePlan

§  for portfolio of investments

§  with sensitivity to risk tolerance

§  for risk sharing

Decreasing risk aversion, logarithmic utility model

5.  Assignment for Real-time Modeling Exercise

There is no preparation in advance for this class!  In class, I will hand out a one-page problem situation. We'll work through the analysis together during class time.  This is an opportunity to develop real-time problem solving skills. It is good preparation for some of the problem-based interviews you will have later in the year.   Since there is no assignment for this class, use your excess preparation time completing the Risk_Preference_Utility_Math tutorial or reviewing previous material or preparing the following day's case. 

6.  Assignment for Marsh and McLennan

Prepare: Marsh & McLennan (A) (9-171-303, Rev 8/26/92)

Reference:  "Risk Preference and Utility," chapter 9 of Quantitative Business Analysis: Text and Cases, by Bodily, Carraway, Frey, and Pfeifer,  pages 126-131.

Assignment Questions:

1. Develop a simulation model for comparing the alternative insurance plans, including the alternative to self-insure. You may use the worksheet MARSHMC.XLS in the MDM library.

2. Carry out a simulation of the two plans.   

3. Which plan would you recommend to Eastern? What is the best way to compare the plans?

4.  Suppose that Marsh and McLennan is decreasingly risk averse with a logarithmic utility function

            u(x) = ln (x+A) where x is the value of their losses, a negative number.

What plan would you select if A is $60 million?  $150 million?  Don't forget the self-insure alternative as you do this.  

Objectives:

Modeling of discrete event simulation

§  distribution for events

§  calculation of payoff

§  distribution for payoff

Comparing risk profiles

§  expected value  and standard deviation

§  cumulative distribution

§  expected utility in a simulation

7.  Assignment for Stars and Stripes

Prepare:  Stars and Stripes: Quest to Bring Home America's Cup, (UVA-QA-0563-M), student version 2.7 from this URL:

http://it.darden.virginia.edu/intranet/case/starsstripes/darden/content/index.htm

Assignment Questions:

1. Which yacht do you recommend?  Please use the Your Decision link from the case to vote your recommendation (while connected to the Internet).

2.  Be prepared to offer supporting analysis.

You may make use of the spreadsheet LVchallengerseriesmodel.xls in the MDM library in your preparation.

Note:  while the rules may be different now, at the time of the case the challenger must use the same boat in the America's Cup challenge that they used in the round robin and the Luis Vuitton Cup semi-final and final.  On the other hand the defender can pick a boat after the Luis Vuitton Cup is finished and just before the America's Cup final is raced.  Use these assumptions from the time of the case in your preparation.

Objectives:

Simulating an entire system for uncertain conditions

§  race

§  series

§  tournaments

Using simulation for design

8.  Assignment for Zeckendorf

Prepare: The Zeckendorf Company (9-186-135, Rev 3/29/94)

Assignment Questions:

1. Be prepared to discuss Zeckendorf's exposure to increases in the commercial paper interest rate on this deal, depending on which of the various financing alternatives they take (completely variable, completely fixed, 9% cap, etc.).

2. Use Crystal Ball to simulate future interest rates. A way to generate future interest rates is by using a random walk relationship:

Next Month's Rate = This Month's Rate + CB.NORMAL(0,.5%)

How would you estimate the standard deviation to use in the normal (.5% is just a first-try figure).

3. William Zeckendorf's risk preference was assessed using lottery questions.  This resulted in a utility curve for the interest cost in this deal, as shown below. This curve doesn't fit any of the standard utility models. However, the curve fits reasonably well with the following piecewise linear curve in total interest cost (Cost):

If Cost is below 6 million, then Utility = 144 - 11*Cost/1,000,000

If Cost is between 6 and 7 million, then Utility = 372 - 49*Cost/1,000,000

If Cost is between 7 and 8 million, then Utility = 232 - 29*Cost/1,000,000

wpe1.jpg (26739 bytes)

Note that the file ZECENDO.XLS, which contains the loan schedule, and ZECINT.XLS, which contains the interest rates in Exhibit 2, are in the MDM library.

(Optional)  I would encourage individuals or, perhaps, pairs of students to create Excel files with the results of their preparation and to please send me these files by email by 8 a.m. before class.  

I recommended individuals to complete the following, if you haven't done so and the use of expected utility for risk preference needs more clarity:

Complete levels 3 and 4 of the Risk_Preference_Utility_Math quiz on the Darden BusinessMath site. This is located at <http://it.darden.virginia.edu/businessmath/>.  If you used it before, you may pick up where you left off before. 

Objectives:

Compare fixed, floating, and capped alternatives

Introduction to random walk

§  what model

§  what standard deviation

Experience using a general utility function

9.  Lecture on Simulation of Prices, Rates, and Cash flows

Prepare:  Simulation of Prices, Rates and Cash Flows (A) (9-203-056)

Assignment Questions: 

Use the data for West Texas Intermediate crude oil spot prices in the WTI worksheet of the file CFETOOLS.XLS, for the following questions, as you prepare the note.

1.  Assuming oil prices follow a geometric random walk, what are the appropriate drift and volatility?  Is Xt+1/Xt normally distributed?
2.  Assuming oil prices follow a mean-reverting process, what is the speed of mean reversion and the implied long-run oil price?  What is the volatility?  Is the empirical residual distribution normal?
3.  For both processes, what is the probability that oil prices will at least double in a year?  Do these numbers seem realistic?
4.  Compare these two models oil prices for use in short-term and long-term models.

Bring any questions regarding anything we have done so far in the course, which we will consider as time allows. 

Objectives:

Additive and multiplicative random walks

Drift

Mean-reversion

Estimation and tests of models

10.  Assignment for ChinaCarb

Prepare:  ChinaCarb(UVA-QA-0759)

1 What does ChinaCarb produce and how is it used in our daily lives? Why or why not is this a good business for them to continue?

2.  Review the various approaches that you know for modeling the simulation of the future price per ton of Catyl65SO over time.  Using the data in case Exhibit 1, recommend a good model and estimate its parameters.

3.  What are the alternatives available to the owners of ChinaCarb? Assume that the owners of ChinaCarb are constantly risk-averse for the purposes of this decision. What do you recommend they do? If the success probability for transferring the technology to production were lower, say 50%, what would you recommend to the owners?

4. How would you make this a more attractive business with less risk?   What ideas do you have for improving the set of opportunities available to ChinaCarb?

Individually or in a group, prepare a PowerPoint file containing 1 or 2 slides for each of questions 2,3,4 (maximum 6 slides).  Please upload your PowerPoint file at the course assignment drop box at MDM Course Folder and bring it to class.

 

Please upload by 8:00 a.m. on the class day your PowerPoint file using the standard upload procedure. Name your file CHI followed by concatenated names of the members of your group: 

CHISurnamGivenm SurnamGivenm SurnamGivenm...., where Surnam denotes the first six letters of a surname and Givenm denotes the first six letters of a given name.

 

Use the spreadsheet ChinaCarb Exhibits.xlsx in your preparation.

Objectives:

Estimating a random walk

§  What model? 

§  Estimation of parameter sensitivity

Project analysis

§  Risk

§  Sensitivity

Creating value and reducing risk

11.  Assignment for Scor-eStore.com

Read:  Real Options (UVA-QA-0639)

Prepare:  Scor-eStore.com  (UVA-QA-0581, Rev. 04/05)

Assignment Questions:    

1.   Using just paper, pencil, and a calculator, determine the value of the first two ideas of Bernard’s friends, over and above the base value of the opportunity already calculated by Bernard.

2.  Making use of Monte Carlo simulation, value the last two ideas offered by Bernard’s friends.   Make use of the spreadsheet in Exhibit 2 of the case, which can be found in the MDM library or downloaded by right-clicking this link: ScoreStoreBase2cb.xls.

3.  Does Bernard have reasonable cutoff levels to trigger action on each of the ideas in question 2?

4.  Should Bernard invest in the business?

5.  Test your option intuition--What would the addition of more uncertainty (wider probability distributions or additional uncertainties) do to the values found in questions 1 and 2?

6.  Are there other contingent opportunities that would add value to this business?  Think of some generic types of ideas that may be relevant here, without valuing them.

Objectives:

Introduction to real option analysis

§  With decision trees

§  With Monte Carlo simulation

Triggers for downstream exercise decisions

§  What to use as triggering quantity

§  How to find the best trigger level

The value of options thinking

12 Assignment for John Carter: Hedging

Reading:  Risk Exposure and Hedging (UVA-QA-0595)
                Using OptQuest (UVA-QA-0594)
                Correlations in Crystal Ball (UVA-QA-0593)

Prepare:  John Carter: Hedging (UVA-QA-0596)

Reference: Risk Preference and Utility (chapter 9 of Quantitative Business Analysis: Text and Cases, by Bodily, Carraway, Frey, and Pfeifer).

Data Spreadsheet:  The data in Exhibit 1 of the case can be found in the MDM spreadsheet folder or downloaded by right-clicking this link: John Carter Data.xls.

Assignment Questions:

1.  Assume that the production quantity of John Carter's farm is known with certainty. Is it a good idea to hedge half of the production? How much should John Carter hedge?  Note:  there are 2000 pounds in a ton. 

2.  Now assume that the output quantity is uncertain. How does the correlation between output and prices affect John Carter’s decision on how much to hedge? Please prepare your analysis showing hedging decisions for correlations of -.99, 0, and .99.

3.  Assuming output quantity is uncertain, how much should John Carter hedge?

If you choose to run Optquest, for simplicity, run discrete levels stepped 100 tons apart with a large number of trials in the simulations.

Please submit your Excel workbook file for John Carter to me by 8 a.m. on the day of class. Please put in separate worksheets of your workbook

a) the basic model

b) statistics of hedged and unhedged simulation runs (use "extract data" of Crystal Ball)

c) your recommendations for the questions, given the Optquest or other analysis you
did.

Name your file CARSurnamGivenm, where Surnam is the first six letters of your surname and Givenm is the first six letters of your given name.  Submit your file by using the usual upload procedure to the course Assignment Drop Box at MDM Course Folder

Objectives:

Understand hedging as a tool to reduce risk (and maybe add value)

Hedging is meant to reduce exposure; knowing exposures is key

§  Depends on payoff interactions of variables  

§  Correlations among quantities

Appeal of hedging depends on risk aversion 

13.  Assignment for McKinsey Guest Case 

Optional Reading: Organizational Use of Decision Analysis (UVA-QA-0655)

Prepare:   Peregrine Steel Mill Case

Assignment Questions are at the end of the Peregrine Steel Mill case


Objectives:

Use of external reseach (e.g.,on the internet) to find appropriate supporting data
 
Experience with decision modeling in a consulting framework

14.  Assignment for Enron Corporation's Weather Derivatives (A) and (B)

Prepare:  

Enron Weather Derivatives digital case at this URL:

http://it.darden.virginia.edu/intranet/case/enron1/weather/

Please view this while connected to the local area network at the Darden School to ensure that the video streaming and downloads are fast.  Along with videos, this site also contains PDF (Acrobat) versions of the following cases, which will are provided in hardcopy form: 

1.  Enron Corporation's Weather Derivatives (A)  (UVA-F-1299)

2.  Enron Corporation's Weather Derivatives (B)  (UVA-F-1300)

Reference: Risk Preference and Utility (chapter 9 of Quantitative Business Analysis: Text and Cases, by Bodily, Carraway, Frey, and Pfeifer) (used in class 6)

Assignment Questions:

The primary task is to respond to the following questions regarding the (B) case.  In doing so, please prepare an Excel model and (in a separate sheet of the same workbook file) prepare results from Crystal Ball runs. 

1. Which, if any of the available contracts would you be willing to accept?

2. Which is the best contract for you?

3. If you could design your own contract that would reduce your exposure to the greatest extent, what would it be?

Make use of the data in Exhibit 1 of the (B) case which is downloadable from the MDM spreadsheet library in the course folder, or by right clicking this link to Weather.xls.

In your preparation, if you need to become more familiar with derivatives in general to get started, think about these questions regarding the (A) case:

1. What is the diagram of payoffs at the end of the life of the contract presented in Exhibit 1?

2. What are the pros and cons of weather protection from PNW’s perspective?

3. Why is Enron in this situation?  What does Enron stand to gain?

4. How should Mary Watts proceed to assess, and decide upon, the use of weather protection for PNW?  What criteria should she use to make her decision?

Objectives:
Seeing the relevant risk
Modeling the risk appropriately
The "ideal" hedge

15. Assignment for Petrosupra Exploration

Prepare:  Petrosupra Exploration (UVA-QA-DRAFT)               

Reference:  Using OptQuest (UVA-QA-0594)

Assignment Questions:

1.    First do a risk-neutral analysis.             

a)  How do you model the price of oil, based on the data in the case at the time of the case (not hindsight)? 

b)  How do you model any other uncertainties?  What is the expected monetary value and risk profile of the base opportunity without considering enhanced recovery?  Be very clear about how your spreadsheet model works. You may care to include the influence diagram to document your decision model. 

c)  What is the expected monetary value and risk profile of the total opportunity including enhanced recovery.  Be clear about how you model the opportunity represented by enhanced recovery and the decision whether to do it.

2.    Now consider risk aversion in your analysis.  What would be the certainty equivalent for  the total opportunity including enhanced recovery.

3. a) Consider each of the three deals with Claiborne Chemical, one by one, from a conceptual standpoint.  For each deal, do you think that deal would be   preferable to Petrosupra versus  no arrangement with Claiborne, assuming   Petrosupra has no other exposure to oil price risk? Was it wise for Claiborne to   be willing to offer each of these deals, assuming they had no other use for oil or   exposure to the price of oil? 

   b)  What should Petrasupra do about the project in light of the Claiborne offer? If you wish to simplify matters here by treating the decision about the enhanced recovery the same way you did in question 1, that is fine.  If you can go beyond the 50-50 split to find what share of the Claiborne commitment should be traded for what share of the LaFource opportunity, you will earn the special title of supermodeler.    

4.  What suggestions do you have for making the opportunity even better?  How might you begin to model and evaluate these ideas?

Please make use of the spreadsheet OILPRICES.XLS in your preparation.

Objectives:
Review random walk
Analyze multiple downstream decisions and options
Build intuition
Finding optimal decision variables using Optquest


Thanks for your work in the class.  Happy Modeling!