Chapter 13 Discussion Questions (Schroeder, 2007)
Question 1. A batch scheduling task of a hospital (a) is assigning in-patients to unit-, surgery-, recovery-, and/or laboratory-testing (e.g., X-rays) rooms. For most of the surgery patients, presumably surgeons have hours and days of the week, implying rooms, anesthesiologists, nurses, and other required staff will be available at those times and at times pre- and post surgery. Scheduling must also account for patients needing emergency surgery or non-surgery hospitalizations attributable to causes such as heart- and other attacks and to accidents. Hospitals providing outpatient services must have schedules for use of equipment and staff needed for X-rays, ultra-sound, mammograms, etc. Thus most hospital scheduling involves staff, but also some equipment.
Universities (b), like hospitals, provide services rather than products, but the services, of course, permit greater scheduling predictability, for example, students don’t require scheduling that allows emergency educations (despite possible needs!). Since most students probably own personal computers, and since most individual teachers, administrators, and clerical workers probably are provided with a computer and each university division probably is assigned its own copying and other equipment, there also are even fewer scheduling needs involving equipment than at hospitals. In scheduling courses to rooms, universities have at least approximations of numbers of undergraduates at each of the four years to graduation and the number of graduate students, along with approximations of the numbers of students majoring in or doing graduate work in each department and the number of those who have not yet declared a major. Schedules must reflect the appropriate numbers of students in each course, and classrooms and text book orders must be of adequate size. Scheduling course times must account for a variety of times for students to be able to meet university and departmental requirements.
Unlike hospitals and universities, movie-making (c) companies provide products, i.e., movies. It isn’t clear when a decision is made to schedule production of a screenplay. Presumably, an executive at the movie studio purchases through an agent either rights to a book, screenplay, or outline, which may or may not have first been purchased by a director, and once there is a screenplay, a decision is made about scheduling production. In examining the information on DVD boxes, the name of the studio is followed by the name of the producer (who may or may not also be the director and screenwriter), for example, “Paramount Pictures presents a Robert Stigwood production” or “Universal Pictures presents a Steven Spielberg film.” Presumably, once the name following the name of a studio is determined, schedules are prepared for these movies, including priority ordering of the movies to be scheduled. “Queues” would include estimates of the time required for production, availability of sound stages and equipment for movies or parts of movies shot at the studio, of equipment and operators of equipment for movies shot on location, availability of particular directors (assuming the director is not also the producer) and actors for major parts, etc. Presumably, once decisions such as these have been made, there need to be schedules for individual movies for purposes including hiring what seem to be the millions of names one sees following a movie (e.g., “best boy,” “head grip,” “assistant to the assistant of assistant costume designer”).
Like a movie studio, a make-to-order factory (d) provides a product. The product is one where specifications were obtained for an individual customer (e.g., by a tailor for a custom-made suit). Batch scheduling would include the orders, time required to fill the orders, time required to obtain required materials (e.g., cloth imported from England), availability of rooms containing necessary equipment, etc.
Question 2. Goldratt’s theory of constraints (pp. 300-302) is based on an assumption for businesses that provide products that may or may not be generally applicable, that the “only goal of operations . . . is to make money” (p. 300). However, for both businesses that provide products and those that provide services, the theory is useful in the sense that one should first identify the main objective and then identify and try to solve particular areas (“bottlenecks”) that interfere with meeting the objective.
The main objective of hospitals (a) should be to use all available funds to provide patients with the highest possible quality of medical services. Through the media, we have heard about the nursing crisis, difficulties in hiring well-qualified nurses, resulting in what probably is a combination of too high a ratio of nurses to patients and unsatisfactory performance of those nurses who are hired. The same problem exists for nursing assistants. Another debated hospital practice has been introducing the practice of using physicians who may not have received high-quality training as “hospitalists.” Clearly, perceived problems such as these require exploring options for solutions.
Regarding universities (b), the main objective should be to use all available funds to provide students with the highest possible quality of education. Situations that students and some faculty perceive as interfering with this objective include lack of available space in classes required of students, classes that seem to be required for the purpose of resolving “turf” battles between departments, and classes that are inappropriately large. At major universities, students have reported that many classes are taught by graduate assistants, which may actually be a problem of lack of “truth in advertising.” Courses should not be listed as taught by “Professor Hotshot” unless this professor actually does teach the course. While government and other external funding has resulted in some pretty silly choices, high-quality research also is funded, which should enhance, rather than interfere with, the quality of education received by students, for example, providing funding to pay graduate- and sometimes undergraduate students to assist with and learn about conducting research. Grants also typically include funds to hire qualified instructors to teach the courses “Professor Hotshot” cannot because he or she is engaged in (hopefully) high-quality research. There is no reason to assume that qualified teachers who do not conduct externally funded research provide poorer-quality instruction than Professor Hotshot. In general, to meet the university’s main objective, allocation of available funds should be examined, for example, is there really enough necessary work so that a Vice Chancellor needs two office assistants and an Assistant to the Vice Chancellor, as well as an Assistant Vice Chancellor, who also needs a couple of assistants?
The main objective of a movie-making (c) studio probably is to make as much money as possible. However, it should be clear that the profits earned by a movie are not reflected by the number of people who buy tickets or DVDs to see the movie. For example, a movie with a budget of $3 million that earns $2 million is a financial disaster, while low-budget movies that earn half a million dollars are financial successes. The successes of a number of movies in the latter categories (high-budget disasters and low-budget successes) are difficult to predict, so solutions are unclear and not necessarily possible. However, studios apparently do know that some fairly low-budget movies will earn a highly predictable and respectable, though not large, profit. For example, some of the best and most highly paid actors are willing to be very poorly paid to appear in Woody Allen movies, for where there are reliable, if not large, audiences, as well as the new generations of audiences that result in movies becoming classics (e.g., Alfred Hitchcock movies). Regarding efficient use of funds, the credits at the end of most movies alone suggest ways to reduce costs – but it is hard to imagine those in the movie “biz” willingly giving up an “assistant to the assistant of the head ‘best boy’!”
While an objective of a make-to-order factory (b) is to earn maximum profits, one would hope that those who make this type of product also have an objective of earning the pride of making a high-quality product. One also would hope that in any business, objectives are within the framework of being met with ethical guidelines (e.g., not permitting sub-standard, even if legal, working conditions). Situations that interfere with the objectives of such businesses include late delivery of materials, in turn, resulting in delays so that more time is needed using key equipment that had been fully scheduled for other jobs. Depending on the product, those that are custom made typically require some employees with particular talents (e.g., tailors at businesses producing custom-made suits), so that replacing such an employee would create a larger delay than in businesses producing other products (e.g., suits bought “off the rack”).
Question 3. A batch schedule consists of “a network of queues” (p. 294) in the sense that jobs or customers are on line for use of a number of different requirements (e.g., equipment, space) for completion of each job. The queues are interconnected because, for example, an under- or overestimate of the time required by one job on the queue for a particular equipment room not only influences the queues following the ones for that job, but also the queues following the jobs behind the one for which time had been under- or overestimated. Overestimates could result in idle time for “bottleneck operations” (p. 300) that could have been used on other jobs and underestimates could result in longer waiting times at bottleneck- and other queues for both the job with the underestimate and for jobs following it in queues, along with missed deadlines for these jobs.
Schroeder, R. G. (2007). Operations management: Contemporary concepts and cases (4th ed.).
New York: McGraw Hill Irwin.