Chapter 12 Managing Waiting Lines McGraw-Hill/Irwin Service Management: Operations, Strategy, and Information Technology, 6e Copyright © 2008 by The McGraw-Hill Companies, Inc. All Rights Reserved.

Learning Objectives Describe the economics of waiting lines using examples. Describe how queues form. Apply Maister’s two “laws of service.” Describe the four psychology of waiting components and suggest strategies to deal with each. Describe the four principles of waiting line management. Describe the essential features of a queuing system. Describe the relationship between a negative exponential distribution of time between arrivals and a Poisson distribution of arrival rates. 12-2

Where the Time Goes In a life time, the average person will spend: SIX MONTHS Waiting at stoplights EIGHT MONTHS Opening junk mail ONE YEAR Looking for misplaced 0bjects TWO YEARS Reading FOUR YEARS Doing housework FIVE YEARS Waiting in line SIX YEARS Eating 12-3

Cultural Attitudes “Americans hate to wait. So business is trying a trick or two to make lines seem shorter…” The New York Times, September 25, 1988 “An Englishman, even when he is by himself, will form an orderly queue of one…” George Mikes, “How to be an Alien” “In the Soviet Union, waiting lines were used as a rationing device…” Hedrick Smith, “The Russians” 12-4

Waiting Realities Inevitability of Waiting: Waiting results from variations in arrival rates and service rates Economics of Waiting: High utilization purchased at the price of customer waiting. Make waiting productive (salad bar) or profitable (drinking bar). 12-5

Laws of Service Maister’s First Law: Customers compare expectations with perceptions. Maister’s Second Law: Is hard to play catch-up ball. Skinner’s Law: The other line always moves faster. Jenkin’s Corollary: However, when you switch to another other line, the line you left moves faster. 12-6

Approaches to Controlling Customer Waiting Animate: Disneyland distractions, elevator mirror, recorded music Discriminate: Avis frequent renter treatment (out of sight) Automate: Use computer scripts to address 75% of questions Obfuscate: Disneyland staged waits (e.g. House of Horrors) 12-7

Essential Features of Queuing Systems Departure Queue discipline Arrival process Queue configuration Service process Renege Balk Calling population No future need for service 12-8

Arrival Process StaticDynamic AppointmentsPrice Accept/Reject BalkingReneging Random arrivals with constant rate Random arrival rate varying with time Facility- controlled Customer- exercised control Arrival process 12-9

Distribution of Patient Interarrival Times 12-10

Temporal Variation in Arrival Rates 12-11

Poisson and Exponential Equivalence Poisson distribution for number of arrivals per hour (top view) One-hour interval Arrival Arrivals Arrivals Arrival 62 min. 40 min. 123 min. Exponential distribution of time between arrivals in minutes (bottom view) 12-12

Queue Configurations Multiple Queue Single queue Take a Number Enter

Queue Discipline Queue discipline Static (FCFS rule) Dynamic selection based on status of queue Selection based on individual customer attributes Number of customers waiting Round robinPriorityPreemptive Processing time of customers (SPT or cµ rule) 12-14

Outpatient Service Process Distributions Second Service Appointment ServiceWalk-in Service 12-15

Service Facility Arrangements Service facility Server arrangement Parking lot Self-serve Cafeteria Servers in series Toll booths Servers in parallel Supermarket Self-serve, first stage; parallel servers, second stage Hospital Many service centers in parallel and series, not all used by each patient 12-16

Topics for Discussion Suggest some strategies for controlling variability in service times. Suggest diversions that could make waiting less painful. Select a bad and good waiting experience, and contrast the situations with respect to the aesthetics of the surroundings, diversions, people waiting, and attitude of servers. Suggest ways that management can influence the arrival times of customers. What are the benefits of a fast-food employee taking your order while waiting in line? 12-17

Interactive Exercise The class breaks into small groups with at least one international student in each group, if possible. Based on overseas travel, each group reports on observations of waiting behavior from a cultural perspective

Eye’ll Be Seeing You How are Maister’s First and Second Laws of Service illustrated? What good and bad features of a waiting process are evident? How should Dr. X respond to Mrs. F’s letter? How could Dr. X prevent future incidents? Should customers be rewarded for offering constructive criticism? 12-19

Sample Letter Dear Mrs. F.: I offer my deepest apologies for your recent bad experience on January 5, The treatment you were shown and the length of time you had to wait is completely inexcusable. You and the rest of your family are valued patients of mine and I hope this most unfortunate experience does not cause me to lose your patronage. I personally guarantee that this will not happen again. I hope you will make another appointment with us to have your problem taken care of. This service, of course, will be provided free of charge. Thank you for expressing your concerns. Please let me know immediately if you have any other problems. Sincerely yours, Dr. X, M.D