The following scenario was written by a reporter who became a Taco Bell worker for a few hours to experience what it’s like to work at one of the most high-tech quick-serve restaurant chains in the world. As you read, visualize how you could analyze a Taco Bell using the queuing models we discussed in this chapter. After the scenario, we will give you some hints related to how you can model the Quick Service (QS) restaurant and then ask a series of questions related to your model. It must always be, “Hi, how are you today?” Never, “Hi, how are you?” “Hi, how’s it going?” or “Welcome to Taco Bell.” Never, “What will it be today?” or, even worse, “What do you want?” Every Taco Bell Service Champion memorizes the order script before his first shift. The folks who work the drive-thru windows at the Taco Bell here in Tustin, California, about 35 miles south of Los Angeles, and everywhere else, are called Service Champions. Those who work the food production line are called Food Champions. You think you know it—“Hi, how are you today?” It seems easy enough. And you follow that with, “You can order when you’re ready,” never “Can I take your order?” The latter puts pressure on the driver, who might be a distracted teenager busy texting her friend or a soccer mom with a half-dozen kids in the van. “They don’t need the additional pressure of a disembodied voice demanding to know their order,” explains Mike Harkins. Harkins, 49, is vice president of One System Operations for Taco Bell, which means he spends all day, every day, thinking about the kitchen and the drive-thru. He has been prepping me for my debut at the window. Getting ready, I wash my hands, scrubbing for the mandated 20 seconds; slide on rubber gloves; and don the three-channel headset that connects me to the ordering station out in the lot, as well as to my fellow Champions. I take my place at the window. I hear the ding indicating a customer has pulled into the loop around the restaurant, and I immediately ask, “Hi, how’s it going?” It gets worse from there. As a Service Champion, my job is to say my lines, input theorder into the proprietary point of sale (POS) system, prepare and make drinks like Limeade Sparklers and Frutista Freezes, collect bills or credit cards, and make change. I input Beefy Crunch Burritos, Volcano Burritos, Chalupas, and Gorditas. My biggest worry is that someone will order a Crunchwrap Supreme, a fastfood marvel made up of two kinds of tortillas, beef, cheese, lettuce, tomatoes, and sauces, all scooped, folded, and assembled into a handheld, multiple-food-group package, which then gets grilled for 27 seconds. This actually doubles the time it takes to prepare a normal order. An order for a Crunchwrap Supreme, the most complex item on the menu, sometimes requires the Service Champion to take up a position on the food production line to complete it in anything like the 164 seconds that Taco Bell averages for each customer, from driving up to the ordering station to pulling away from the pick-up window. Above me on the wall, a flat-screen display shows the average time of the last five cars at either the order station or the pick-up window, depending on which is slowest. If the number is red, as it is now, that means one, or both, of the waits is exceeding 50 seconds, the target during peak periods. It now shows 53 seconds, on its way to 60, 70 . . . and then I stop looking. The highpitched ding that announces each new customer becomes steady, unrelenting, and dispiriting— 85 cars will roll through over the peak lunch rush. And I keep blowing the order script. I fall behind so quickly and completely that restaurant manager Amanda Mihal, a veteran of 12 years in the QSR business (Quick Serve Restaurant, the acronym for an industry that makes acronyms for everything), has to step in. “You’ll get it,” Amanda says as she fixes an order that I have managed to screw up. “Eventually.” Every Taco Bell has two food production lines, one dedicated to the drive-thru and the other to servicing the walk-up counter. Working those lines is no easier than wearing the headset. The back of the restaurant has been engineered so that the Steamers, Stuffers, and Expeditors, the names given to the Food Champions who work the pans, take as few footsteps as possible during a shift. There are three prep areas: the hot holding area, the cold holding area, and the wrapping expediting area. The Stuffer in the hot holding area stuffs the meat into the tortillas, ladling beef with Taco Bell’s proprietary tool, the BPT, or beef portioning tool. The steps for scooping the beef have been broken down into another acronym, SST, for stir, scoop, and tap. Flour tortillas must be cooked on one side for 15 seconds and the other for five. When I take my place on the line and start to prepare burritos, tacos, and chalupas—they won’t let me near a Crunchwrap Supreme—it is immediately clear that this has been engineered to make the process as simple as possible. The real challenge is the wrapping. Taco Bell once had 13 different wrappers for its products. That has been cut to six by labeling the corners of each wrapper differently. The paper, designed to slide off a stack in single sheets, has to be angled with the name of the item being made at the upper corner. The tortilla is placed in the middle of the paper and the item assembled from there until you fold the whole thing up in the wrapping expediting area next to the grill. “We had so many wrappers before, half a dozen stickers; it was all costing us seconds,” says Harkins. In repeated attempts, I never get the proper item name into the proper place. And my burritos just do not hold together. With me on the line are Carmen Franco, 60, and Ricardo Alvarez, 36. The best Food Champions can prepare about 100 burritos, tacos, chalupas, and gorditas in less than half an hour, and they have the 78-item menu memorized. Franco and Alvarez are a precise and frighteningly fast team. Ten orders at a time are displayed on a screen above the line, five drive-thrus and five walk-ins. Franco is a blur of motion as she slips out wrapping paper and tortillas, stirs, scoops, and taps, then slides the items down the line while looking up at the screen. The top Food Champions have an ability to scan through the next five orders and identify those that require more preparation steps, such as Grilled Stuffed Burritos and Crunchwrap Supremes, and set those up before returning to simpler tacos and burritos. When Alvarez is bogged down, Franco slips around him, and slides Crunchwrap Supremes into their boxes. At the drive-thru window in Tustin, I would have shaken off the headset many orders ago had it not been for manager Mihal’s support, but I’m hanging in there. After a while, I do begin to detect a pleasing, steady rhythm to the system, the transaction, the delivery of the food. Each is a discrete, predictable, scripted interaction. When the order is input correctly, the customer drives up to the window, the money is paid, the Frutista Freeze or Atomic Bacon Bomber (a test item specific to this Taco Bell) handed over, and you send people on their way with a smile and a “Thank you for comingto Taco Bell,” you feel a moment of accomplishment. And so does Harkins, for it has all gone exactly as he has planned. Then a ding in my headset. “Um, hello?” Idiot, I think to myself, I’ve blown the script again. Source: Karl Taro Greenfeld, Bloomberg BusinessWeek, Features Section, May 5, 2011. Modeling the Restaurant In the scenario, they indicate that it takes about 164 seconds, on average, to serve a customer during the busy lunch-hour period. Put yourself in the seat of your car getting food at the QS restaurant. Let’s assume you are using the drive-thru window and that you will pick up the food and take it home to eat with some friends. You drive into the restaurant lot and notice a line of cars has formed at the order kiosk. You wait for your turn to talk to the Customer Service Champion so you can place your order. The menu is clearly in view, so you can see exactly what you want. Soon it is your turn and you quickly place your order, learn what the bill will be, and move your car to the line at the drive-thru window. While waiting, you get your money out and count out the exact change you will need. After a short time, it’s your turn at the window and you give the Service Champion your money, take your drink and food, and carefully drive out of the parking lot. Think about what happened at the restaurant. First, you waited in two lines. The first was at the order kiosk and the second at the drive-thru window. Next, consider the work the restaurant needed to complete to process your order. The Service Champion took your order and entered it in the POS system, prepared your drink, and then, when the food was ready, collected your money, and delivered your drink and food. One of the Food Champions prepared your food using information from a screen that shows orders as they are entered by the Service Champion. The total time it takes between when you arrive at the restaurant until you leave is made up of the following elements: 1. The service time for the Service Champion to process your order. 2. The service time for the Food Champion to prepare your order. 3. The waiting while the Service Champion and Food Champion serve other customers. To model this using the queuing models in the chapter, assume you have two totally independent service processes. The first process is the Service Champion and the second is the Food Champion. Each process has potentially a different mean service time per customer. The Service Champion must serve each customer, and they arrive at a particular rate. The Food Champion prepares the individual items on the order such as a burrito, taco, chalupa, or gorditas taco. As the orders are taken, each individual item appears on a monitor telling the Food Champion what should be made next. The average time for a customer to run through the system is the sum of the average service times (time to take the order by the Service Champion and time to make the order by the Food Champion) plus the sum of the expected waiting times for the two processes. This assumes these processes operate totally independent of each other, which might not be exactly true. But we leave that to a later discussion. Assume that the queues in front of each process are large, meaning there is plenty of room for cars in the line before and after the order kiosk. Also, assume there are a single Service Champion and two Food Champions each operating independently and working just on the drivethru orders. Also, assume that the arrival pattern is Poisson, customers are handled first come, first served, and the service pattern is exponential. Given this, answer the following questions: 1. Draw a diagram of the process using the format in Exhibit 9.5. 2. Consider a base case where a customer arrives every 40 seconds and the Customer Service Champion can handle 120 customers per hour. There are two Food Champions, each capable of handling 100 orders per hour. How long should it take to be served by the restaurant (from the time a customer enters the kiosk queue until her food is delivered)? Use queuing models to estimate this. 3. On average, how busy are the Customer Service Champions and the two Food Champions? 4. On average, how many cars do you expect to have in the drive-thru line? (Include those waiting to place orders and those waiting for food.) 5. If the restaurant runs a sale and the customer arrival rate increases by 20 percent, how would this change the total time expected to serve a customer? How would this change the average number of cars in the drive-thru line? 6. Currently, relatively few customers (less than ½ percent) order the Crunchwrap Supreme. What would happen if the restaurant ran the sale, demand jumped on the Crunchwrap Supreme, and 30 percent of the orders were for this item? Take a quantitative approach to answering this question. Assume that the Customer Service Champion never helps the Food Champions and that these two processes remain independent. 7. For the type of analysis done in this case, what are the key assumptions? What would be the impact on our analysis if these assumptions were not true? 8. Could this type of analysis be used for other service- type businesses? Give examples to support your answer.
> Various financial data for the past two years follow. Calculate the total productivity measure and the partial measures for labor, capital, and raw materials for this company for both years. What do these measures tell you about this compa
> Compare the importance and relevance of quality control in JIT, MRP, and synchronous manufacturing.
> A U.S. manufacturing company operating a subsidiary in an LDC (less-developed country) shows the following results: a. Calculate partial labor and capital productivity figures for the parent and subsidiary. Do the results seem misleading
> Sailmaster makes high-performance sails for competitive windsurfers. Below is information about the inputs and outputs for one model, the Windy 2000. Calculate the productivity in sales revenue/labor expense. Units sold 1,217 Sale price each $1,70
> What methodology is used to assess a client’s performance relative to the expectations of its customers or the performance of its competitors?
> Daily demand for a product is 60 units with a standard deviation of 10 units. The review period is 10 days, and lead time is 2 days. At the time of review, there are 100 units in stock. If 98 percent service probability is desired, how many units should
> Find examples where companies have used features related to environmental sustainability to win new customers.
> In manufacturing, quality measures are largely based on hard evidence. In health care, quality and service measures are largely based on what?
> What relationship is there between learning curves and productivity measurement?
> Why is simulation often called a technique of last resort?
> What do the expressions order winners and order qualifiers mean? What was the order winner(s) for your last purchase of a product or service?
> What are the pro and cons of relocating a small or midsized manufacturing firm (that makes mature products) from the United States to China?
> Why does the proper operations and supply chain strategy keep changing for companies that are world-class competitors?
> What are the major priorities associated with operations and supply chain strategy? How has their relationship to each other changed over the years?
> What is meant by triple-bottom-line strategy? Give an example of a company that has adopted this type of strategy.
> What are characteristics of efficient, responsive, risk-hedging and agile supply chains? Can a supply chain be both efficient and responsive? Risk-hedging and agile? Why, or why not?
> List at least three significant ways in which service systems differ from manufacturing systems.
> Some manufacturing firms contract with an outside company to manage the firm’s logistics functions. What is the general term for a firm that provides such services?
> What do we mean when we say productivity is a relative measure?
> Will the Human Resource Management (HRM) policies of a firm have much of an effect on the learning rates the firm may be able to achieve?
> Identify an operations and supply chain - related disruption that recently impacted a company. What could the company have done to have minimized the impact of this type of disruption prior to it occurring?
> What mode of transportation is limited to specialized products such as liquids and gases?
> Retailers Warehouse (RW) is an independent supplier of household items to department stores. RW attempts to stock enough items for a 98 percent service probability. A stainless steel knife set is one item it stocks. Demand (2,400 sets per year) is relati
> Hospitals are major users of poka-yoke (fail-safe) devices. Can you think of any?
> What is the term used to refer to the application of the scientific method to evaluate alternative treatment methods and create guidelines for similar clinical situations?
> Item X is a standard item stocked in a company’s inventory of component parts. Each year, the firm, on a random basis, uses about 2,000 of item X, which costs $25 each. Storage costs, which include insurance and cost of capital, amount to $5 per unit of
> S. L. P. Craft would like your help in developing a layout for a new outpatient clinic to be built in California. From analysis of another recently built clinic, she obtains the data shown in the following diagram. This includes the number of trips made
> Look at the job postings at http://www.apics.org and evaluate the opportunities for an OSM major with several years of experience. There are pages and pages of these in the APICS Career Center. Here are some examples: Global Active Ingredient Supply Pla
> Which major OSCM concept can be described as an integrated set of activities designed to achieve high-volume production using minimal inventories of parts that arrive at workstations exactly when they are needed?
> Order the following major concepts that have helped define the OSCM field on a time line. Use 1 for the earliest to be introduced, and 5 for the most recent. Supply chain management Manufacturing strategy de
> At times in the past, the dollar showed relative weakness with respect to foreign currencies, such as the yen, mark, and pound. This stimulated exports. Why would long-term reliance on a lower valued dollar be at best a short-term solution to the compe
> What is the difference between a service and a good?
> The learning curve phenomenon has been shown in practice to be widely applicable. Once a company has established a learning rate for a process, they can use it to predict future system performance. Would there be any reason to reevaluate the process’ lea
> What is product-service bundling and what are the benefits to customers?
> Match the following OSCM job titles with the appropriate duties and responsibilities. Plant manager A. Plans and coordinates staff activities such as new product development and new facility location. - Supply chain manager B. Oversees the movement
> A certain custom engraving shop has traditionally had orders for between 1 and 50 units of whatever a customer orders. A large company has contacted this shop about engraving “reward” plaques (which are essentially identical to each other). It wants the
> What is the term used to describe arrangements to move clinical information across various information systems while still maintaining the meaning of the information being exchanged?
> In a data box on a value stream map, what do the abbreviations CT and C/O mean?
> Distinguish between a channel and a phase.
> Which scheduling process drives requirements in the MRP process?
> What service industry has impressed you the most with its innovativeness?
> What mode of transportation is involved in the movement of the greatest number of products?
> Daily demand for a product is 100 units, with a standard deviation of 25 units. The review period is 10 days and the lead time is 6 days. At the time of review, there are 50 units in stock. If 98 percent service probability is desired, how many units sho
> What high-level position manager is responsible for working with the CEO and company president to determine the company’s competitive strategy?
> Define the service package of your college or university. What is its strongest element? What is its weakest one?
> Where would you place Shouldice Hospital on the product–process framework (see Chapter 5 case, “Shouldice Hospital—A Cut Above”)? What are the implications of adding a specialty such as cosmetic surgery?
> What recent changes have caused supply chain management to gain importance?
> Is it possible to achieve zero inventories? Why or why not?
> What was the first major project management information system that is now commonly used for managing very large projects?
> Recently, Phil Harris, the production control manager at Brunswick, read an article on time-phased requirements planning. He was curious about how this technique might work in scheduling Brunswick’s engine assembly operations and d
> Research and compare the inventory turnover ratios of three large retailers: Walmart, Target, and Nordstrom’s. Use the same financial web site for all three, and compare numbers from the same time frame. What do these ratios tell you? Are you surprise
> Why is it desirable to increase a company’s inventory turnover ratio?
> Some people tend to use the terms effectiveness and efficiency interchangeably, though we’ve seen they are different concepts. But is there any relationship at all between them? Can a firm be effective but inefficient? Very efficient but essentially i
> Define process batch and transfer batch and their meaning in each of these applications: MRP, JIT and bottleneck or constrained resource logic.
> Why might managers resist buying a more expensive piece of equipment that is known to have a lower TCO than a less expensive item?
> What is the current “hot area” for operations consultants in both manufacturing and services?
> Have you ever purchased a product based on purchase price alone and were surprised by the eventual TCO, either in money or in time? Describe the situation
> Describe how outsourcing works. Why would a firm want to outsource?
> As a supplier, which factors would you consider about a buyer (your potential customer) to be important in setting up a long-term relationship?
> As in manufacturing, productivity and capacity utilization are important performance measures in health care operations. What are the similarities and differences in how these measures might be used in the two different industries?
> Describe the differences between functional and innovative products.
> Some have argued that for hospitals, both medical schools and nursing schools should be considered part of the supply chain. Do you agree?
> Remote diagnosis uses electronic devices for diagnosing patients at a distance. What is another term used to refer to this practice?
> What is the MRP term for the time periods used in planning?
> What could a hospital learn from benchmarking a Ritz-Carlton Hotel? Southwest Airlines? Disneyland?
> Would you expect the Poisson distribution to be a good approximation of a. Runners crossing the finish line in the Boston Marathon? b. Arrival times of the student in your OM class? c. Arrival times of the bus to you stop at school?
> How does a physician-driven supply chain differ from a typical materials supply chain?
> Could a hospital or physician offer a service guarantee? Explain.
> You have a job assisting the Medical Director at a Family Medical Clinic in New York City. The Medical Director is concerned about the long wait times of patients visiting the clinic and would like to improve operations. The following are facts about the
> List five major reasons why a new electronic components manufacturing firm should move into your city or town?
> Following are the process flow sequences for three products: A, B, and C. There are two bottleneck operations—on the first leg and fourth leg—marked with an X. Boxes represent processes, which may be either machine or
> For the four basic configurations that follow, assume that the market is demanding product that must be processed by both Resource X and Resource Y for Cases I, II, and III. For Case IV, both resources supply separate but dependent markets; that is, the
> The following production flow shows Parts O, Q, and T; Subassembly U; and the final assembly for Product V. M to N to O P to Q R to S to T O and Q to U U and T to V N involves a bottleneck operation, and S involves a capacity-constrained resource. Draw t
> A steel product is manufactured by starting with raw material (carbon steel wire) and then processing it sequentially through five operations using machines A to E, respectively (see following table). This is the only use that the five machines are put t
> List at least four characteristics of a well-designed service system.
> As the degree of customer contact increases in a service operation, what generally happens to the efficiency of the operation?
> Compare and contrast JIT, MRP, and synchronized manufacturing, stating their main features, such as where each is or might be used, amounts of raw materials and work-in-process inventories, production lead times and cycle times, and methods for control.
> An equipment manufacturer has the following steps in its order entry process: a. Take the order and fax it to order entry. b. Enter the order into the system (10 percent unclear or incorrect). c. Check stock availability (stock not available for 15 perce
> Jill’s Job Shop buys two parts (Tegdiws and Widgets) for use in its production system from two different suppliers. The parts are needed throughout the entire 52-week year. Tegdiws are used at a relatively constant rate and are ordered
> The M–N plant manufactures two different products: M and N. Selling prices and weekly market demands are shown in the following diagram. Each product uses raw materials with costs as shown. The plant has three different machines: A, B,
> The following diagram shows the flow process, raw material costs, and machine processing time for three products: A, B, and C. There are three machines (W, X, and Y) used in the production of these products; the times shown are in required minutes of pro
> How might the following business specialists use learning curves: accountants, marketers, financial analysts, personnel managers, and computer programmers?
> Here are average process cycle times for several workcenters. State which are bottlenecks, nonbottlenecks, and capacity-constrained resources. Processing time Setup time Processing time Setup Idle Processing time Setup Idle Processing time Setup Idl
> The following production flow shows Parts E, I, and N; Subassembly O; and the final assembly for Product P. A to B to C to D to E F to G to H to I J to K to L to M to N E and I to O N and O to P B involves a bottleneck operation, and M
> What is required to make cross-docking a viable solution for a logistics provider?
> What is the purpose of value stream mapping? How can this be achieved?
> The accompanying figure shows a production network model with the parts and processing sequences. State clearly on the figure (1) where you would place inventory; (2) where you would perform inspection; and (3) where you would emphasize high-quality outp
> Operations and supply chain management is concerned with the design and management of the entire system that has what function?
> What is the process to ensure that all of the needs for a particular item are calculated at the same time in the MRP process?
> Willard Lock Company is losing market share because of horrendous due-date performance and long delivery lead times. The company’s inventory level is high and includes many finished goods that do not match the short-term orders. Materia
> As shown in the chapter, the effect of learning in a given system eventually flattens out over time. At that point in the life of a system, learning still exists, though its effect continues to diminish. Beyond that point is it impossible to significant
> What are the three financial measurements necessary to adequately measure a firm’s performance?
> Lieutenant Commander Data is planning to make his monthly (every 30 days) trek to Gamma Hydra City to pick up a supply of isolinear chips. The trip will take Data about two days. Before he leaves, he calls in the order to the GHC Supply Store. He uses ch
> What is the name of the software Goldratt developed to implement his idea of TOC?
> The solution to coping with natural differences between marketing and production functions is to do what two things?
> There is an 82 percent chance the following project can be completed in X weeks or less. What is X? B D A C E Activity Most Optimistic Most Likely Most Pessimistic A 2 11 B. 3 3 6. 10 4 7 10 3. 00
> Cost accounting logic can lead managers to keep their resources busy all the time, increasing productivity with no regard to demand. What is the negative result from this effect?
> What type of manufacturing environment is JIT limited to?
> What are the three elements that require integration to be successful in operations and supply chain management?
> How does synchronous manufacturing differ from MRP with respect to scheduling?
