1. © 2008 Prentice-Hall, Inc. Chapter 1 To accompany Quantitative Analysis for Management, Tenth Edition, by Render, Stair, and Hanna Power Point slides created by Jeff Heyl Introduction to Quantitative Analysis © 2009 Prentice-Hall, Inc.

2. © 2009 Prentice-Hall, Inc. 1 – 2 Introduction Mathematical tools have been used for thousands of years Quantitative analysis can be applied to a wide variety of problems It’s not enough to just know the mathematics of a technique One must understand the specific applicability of the technique, its limitations, and its assumptions

3. © 2009 Prentice-Hall, Inc. 1 – 3 Need for Operations Management The increased complexity of running a successful business. Many large companies with complex business processes have used OM for years to help executives and managers make good strategic and operational decisions. American Airlines and IBM have incredibly complex operations in logistics, customer service and resource allocation that are built on OM technologies. As the trend of increased business complexity moves to smaller enterprises, OM will play vital operational and strategic roles.

4. © 2009 Prentice-Hall, Inc. 1 – 4 Need for OM Lots of information, but no decisions. Enterprise resource planning (ERP) systems and the Web have contributed to a pervasive information environment; decision-makers have total access to every piece of data in the organization. The problem is that most people need a way to transform this wealth of data into actionable information that helps them make good tactical and strategic decisions. The role of OM decision methods is to help leverage a company’s investment in information technology infrastructure by providing a way to convert data into actions.

5. © 2009 Prentice-Hall, Inc. 1 – 5 Need for OM A large nationwide bank is using OM techniques to configure complicated financial instruments for their customers. A process that previously required a human agent and took minutes or hours to perform is now executed automatically in seconds on the bank’s Intranet. The resulting financial products are far superior to those produced by the manual process.

6. © 2009 Prentice-Hall, Inc. 1 – 6 Need for OM A major retail enterprise is using OM methodology for making decisions about customer relationship management (CRM). They are using mathematical optimization to achieve the most profitable match between a large number of customer segments, a huge variety of products and services, and an expanding number of marketing and sales channels such

7. © 2009 Prentice-Hall, Inc. 1 – 7 Need for OM Sears, Roebuck and Company Manages a U.S. fleet of more than 1,000 delivery vehicles, some company owned and some not. The company makes more than 4 million deliveries a year of 21,000 uniquely different items. It has 46 routing offices and provides the largest home delivery service of furniture and appliances in the United States. The company also operates a U.S. fleet of 12,500 service vehicles, together with an associated staff of service technicians. Service demand is on the order of 15 million calls per year and revenue generated is approximately $3 billion.

8. © 2009 Prentice-Hall, Inc. 1 – 8 Need for OM OM researchers designed a system to deal with such variables as customer schedules and requested performance times, time estimates for the required service, vehicles and personnel available, skills needed, parts and product availability and so on. The system was designed to automatically schedule all facets of performance in such a way as to Provide accurate and convenient time windows for the Sears customer Minimize costs Maximize certain objective measures of task performance, including customer satisfaction. This effort generated a one time cost reduction of $9 million as well as ongoing savings of $42 million per year.

9. © 2009 Prentice-Hall, Inc. 1 – 9 Examples of Quantitative Analyses Taco Bell saved over $150 million using forecasting and scheduling quantitative analysis models NBC television increased revenues by over $200 million by using quantitative analysis to develop better sales plans Continental Airlines saved over $40 million using quantitative analysis models to quickly recover from weather delays and other disruptions

10. © 2009 Prentice-Hall, Inc. 1 – 10 Meaningful Information Quantitative Analysis Quantitative analysis Quantitative analysis is a scientific approach to managerial decision making whereby raw data are processed and manipulated resulting in meaningful information Raw Data What is Quantitative Analysis?

11. © 2009 Prentice-Hall, Inc. 1 – 11 Quantitative factors Quantitative factors might be different investment alternatives, interest rates, inventory levels, demand, or labor cost Qualitative factors Qualitative factors such as the weather, state and federal legislation, and technology breakthroughs should also be considered Information may be difficult to quantify but can affect the decision-making process What is Quantitative Analysis?

12. © 2009 Prentice-Hall, Inc. 1 – 12 Implementing the Results Analyzing the Results Testing the Solution Developing a Solution Acquiring Input Data Developing a Model The Quantitative Analysis Approach Defining the Problem Figure 1.1

13. © 2009 Prentice-Hall, Inc. 1 – 13 Defining the Problem Need to develop a clear and concise statement that gives direction and meaning to the following steps This may be the most important and difficult step It is essential to go beyond symptoms and identify true causes May be necessary to concentrate on only a few of the problems – selecting the right problems is very important Specific and measurable objectives may have to be developed

14. © 2009 Prentice-Hall, Inc. 1 – 14 Developing a Model Quantitative analysis models are realistic, solvable, and understandable mathematical representations of a situation There are different types of models $ Advertising $ Sales Y = b 0 + b 1 X Schematic models Scale models

15. © 2009 Prentice-Hall, Inc. 1 – 15 Developing a Model Models generally contain variables (controllable and uncontrollable) and parameters Controllable variables are generally the decision variables and are generally unknown Parameters are known quantities that are a part of the problem

16. © 2009 Prentice-Hall, Inc. 1 – 16 Acquiring Input Data Input data must be accurate – GIGO rule Data may come from a variety of sources such as company reports, company documents, interviews, on-site direct measurement, or statistical sampling Garbage In Process Garbage Out

17. © 2009 Prentice-Hall, Inc. 1 – 17 Developing a Solution The best (optimal) solution to a problem is found by manipulating the model variables until a solution is found that is practical and can be implemented Common techniques are Solving Solving equations Trial and error Trial and error – trying various approaches and picking the best result Complete enumeration Complete enumeration – trying all possible values algorithm Using an algorithm – a series of repeating steps to reach a solution

18. © 2009 Prentice-Hall, Inc. 1 – 18 Testing the Solution Both input data and the model should be tested for accuracy before analysis and implementation New data can be collected to test the model Results should be logical, consistent, and represent the real situation

19. © 2009 Prentice-Hall, Inc. 1 – 19 Analyzing the Results Determine the implications of the solution Implementing results often requires change in an organization The impact of actions or changes needs to be studied and understood before implementation Sensitivity analysis Sensitivity analysis determines how much the results of the analysis will change if the model or input data changes Sensitive models should be very thoroughly tested

20. © 2009 Prentice-Hall, Inc. 1 – 20 Implementing the Results Implementation incorporates the solution into the company Implementation can be very difficult People can resist changes Many quantitative analysis efforts have failed because a good, workable solution was not properly implemented Changes occur over time, so even successful implementations must be monitored to determine if modifications are necessary

21. © 2009 Prentice-Hall, Inc. 1 – 21 Modeling in the Real World Quantitative analysis models are used extensively by real organizations to solve real problems In the real world, quantitative analysis models can be complex, expensive, and difficult to sell Following the steps in the process is an important component of success

22. © 2009 Prentice-Hall, Inc. 1 – 22 How To Develop a Quantitative Analysis Model An important part of the quantitative analysis approach Let’s look at a simple mathematical model of profit Profit = Revenue – Expenses

23. © 2009 Prentice-Hall, Inc. 1 – 23 How To Develop a Quantitative Analysis Model Expenses can be represented as the sum of fixed and variable costs and variable costs are the product of unit costs times the number of units Profit =Revenue – (Fixed cost + Variable cost) Profit =(Selling price per unit)(number of units sold) – [Fixed cost + (Variable costs per unit)(Number of units sold)] Profit = sX – [ f + vX ] Profit = sX – f – vX where s = selling price per unit v = variable cost per unit f = fixed cost X = number of units sold

24. © 2009 Prentice-Hall, Inc. 1 – 24 How To Develop a Quantitative Analysis Model Expenses can be represented as the sum of fixed and variable costs and variable costs are the product of unit costs times the number of units Profit =Revenue – (Fixed cost + Variable cost) Profit =(Selling price per unit)(number of units sold) – [Fixed cost + (Variable costs per unit)(Number of units sold)] Profit = sX – [ f + vX ] Profit = sX – f – vX where s = selling price per unit v = variable cost per unit f = fixed cost X = number of units sold The parameters of this model are f, v, and s as these are the inputs inherent in the model The decision variable of interest is X

25. © 2009 Prentice-Hall, Inc. 1 – 25 Bagels ‘R Us Profits = Revenue - Expenses Profits = $1*Number Sold - $100 - $.50*Number Sold Assume you are the new owner of Bagels R Us and you want to develop a mathematical model for your daily profits and breakeven point. Your fixed overhead is $100 per day and your variable costs are 0.50 per bagel (these are GREAT bagels). You charge $1 per bagel. (Price per Unit)  (Number Sold) - Fixed Cost - (Variable Cost/Unit)  (Number Sold)

26. © 2009 Prentice-Hall, Inc. 1 – 26 Breakeven Example f=$100, s=$1, v=$.50 X=f/(s-v) X=100/(1-.5) X=200 At this point, Profits are 0

27. © 2009 Prentice-Hall, Inc. 1 – 27 Pritchett’s Precious Time Pieces Profits = sX – f – vX The company buys, sells, and repairs old clocks. Rebuilt springs sell for $10 per unit. Fixed cost of equipment to build springs is $1,000. Variable cost for spring material is $5 per unit. s = 10 f = 1,000 v = 5 Number of spring sets sold = X –$1,000 If sales = 0, profits = –$1,000 If sales = 1,000, profits= [(10)(1,000) – 1,000 – (5)(1,000)] = $4,000

28. © 2009 Prentice-Hall, Inc. 1 – 28 Pritchett’s Precious Time Pieces 0 = sX – f – vX, or 0 = ( s – v ) X – f break-even point Companies are often interested in their break-even point (BEP). The BEP is the number of units sold that will result in $0 profit. Solving for X, we have f = ( s – v ) X X = f s – v BEP = Fixed cost (Selling price per unit) – (Variable cost per unit)

29. © 2009 Prentice-Hall, Inc. 1 – 29 Pritchett’s Precious Time Pieces 0 = sX – f – vX, or 0 = ( s – v ) X – f break-even point Companies are often interested in their break-even point (BEP). The BEP is the number of units sold that will result in $0 profit. Solving for X, we have f = ( s – v ) X X = f s – v BEP = Fixed cost (Selling price per unit) – (Variable cost per unit) BEP for Pritchett’s Precious Time Pieces BEP = $1,000/($10 – $5) = 200 units Sales of less than 200 units of rebuilt springs will result in a loss Sales of over 200 units of rebuilt springs will result in a profit

30. © 2009 Prentice-Hall, Inc. 1 – 30 Examples 1.Selling price $1.50, cost/bagel $.80, fixed cost $250 Breakeven point? 2.Seeking a profit of $1,000, selling price $1.25, cost/bagel $.50, 100 sold/day. What is fixed cost? 3. What selling price is needed to achieve a profit of $750 with a fixed cost of $75 and variable cost of $.50

31. © 2009 Prentice-Hall, Inc. 1 – 31 Examples Seeing a need for childcare in her community, Sue decided to launch her own daycare service. Her service needed to be affordable, so she decided to watch each child for $12 a day. After doing her homework, Sue came up with the following financial information: Selling Price (per child per day) $12 Operating Expenses (per month) Insurance 400 + Rent 200 = Total OE $600 Costs of goods sold $4.00 per unit Meals 2 @ $1.50 (breakfast & lunch) Snacks 2 @ $0.50 How many children will she need to watch on a monthly basis to breakeven?

32. © 2009 Prentice-Hall, Inc. 1 – 32 Examples Applying the formula, we have: $600/($12-$4) = 75 She has to have a total of 75 children in her program over the month to breakeven. If she is open only 20 days per month then she needs 75/20=3.75 children per day on the average. Expenses per month $600 + 75*$4.00 = $900 Revenue per month 75*$12 = $900

33. © 2009 Prentice-Hall, Inc. 1 – 33 Advantages of Mathematical Modeling 1.Models can accurately represent reality 2.Models can help a decision maker formulate problems 3.Models can give us insight and information 4.Models can save time and money in decision making and problem solving 5.A model may be the only way to solve large or complex problems in a timely fashion 6.A model can be used to communicate problems and solutions to others

34. © 2009 Prentice-Hall, Inc. 1 – 34 Models Categorized by Risk Mathematical models that do not involve risk are called deterministic models We know all the values used in the model with complete certainty Mathematical models that involve risk, chance, or uncertainty are called probabilistic models Values used in the model are estimates based on probabilities

35. © 2009 Prentice-Hall, Inc. 1 – 35 Computers and Spreadsheet Models QM for Windows An easy to use decision support system for use in POM and QM courses This is the main menu of quantitative models Program 1.1

36. © 2009 Prentice-Hall, Inc. 1 – 36 Computers and Spreadsheet Models Excel QM’s Main Menu (2003) Works automatically within Excel spreadsheets Program 1.2A

37. © 2009 Prentice-Hall, Inc. 1 – 37 Computers and Spreadsheet Models Excel QM’s Main Menu (2007) Program 1.2B

38. © 2009 Prentice-Hall, Inc. 1 – 38 Computers and Spreadsheet Models Excel QM for the Break- Even Problem Program 1.3A

39. © 2009 Prentice-Hall, Inc. 1 – 39 Computers and Spreadsheet Models Excel QM Solution to the Break- Even Problem Program 1.3B

40. © 2009 Prentice-Hall, Inc. 1 – 40 Computers and Spreadsheet Models Using Goal Seek in the Break- Even Problem Program 1.4

41. © 2009 Prentice-Hall, Inc. 1 – 41 Computers and Spreadsheet Models Using Goal Seek in the Break- Even Problem Program 1.4

42. © 2009 Prentice-Hall, Inc. 1 – 42 Possible Problems in the Quantitative Analysis Approach Defining the problem Problems are not easily identified Conflicting viewpoints Impact on other departments Beginning assumptions Solution outdated Developing a model Fitting the textbook models Understanding the model

43. © 2009 Prentice-Hall, Inc. 1 – 43 Possible Problems in the Quantitative Analysis Approach Acquiring input data Using accounting data Validity of data Developing a solution Hard-to-understand mathematics Only one answer is limiting Testing the solution Analyzing the results

44. © 2009 Prentice-Hall, Inc. 1 – 44 Implementation – Not Just the Final Step Lack of commitment and resistance to change Management may fear the use of formal analysis processes will reduce their decision-making power Action-oriented managers may want “quick and dirty” techniques Management support and user involvement are important

45. © 2009 Prentice-Hall, Inc. 1 – 45 Implementation – Not Just the Final Step Lack of commitment by quantitative analysts An analysts should be involved with the problem and care about the solution Analysts should work with users and take their feelings into account