EP JOHN

WAITING LINE MANAGEMENT

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 E-mail FOUR YEARS Doing housework FIVE YEARS Waiting in line SIX YEARS Eating

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TEN PROPOSITIONS ON THE PSYCHOLOGY OF

WAITING LINES1. Unoccupied time feels longer 2. Preprocess/post-process waiting feels longer

than in-process3. Anxiety makes waiting seem longer4. Uncertain waiting is longer than known, finite

waiting5. Unexplained waiting seems longer6. Unfair waiting is longer than equitable waiting 7. People will wait longer for more valuable

services8. Waiting alone feels longer than in groups9. Physically uncomfortable waiting feels longer10. Waiting seems longer to new or occasional

users

Sources: Maister; Davis & Heineke; Jones & Peppiatt

COMPONENTS OF THE QUEUING SYSTEM

CustomerArrivals

Servers

Waiting Line

Servicing System

Exit

Queue or

LAWS OF SERVICEMaister’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.

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CUSTOMER SERVICE POPULATION SOURCES

Population Source

Finite Infinite

Example: Number of machines needing repair when a company only has three machines.

Example: Number of machines needing repair when a company only has three machines.

Example: The number of people who could wait in a line for gasoline.

Example: The number of people who could wait in a line for gasoline.

SERVICE PATTERN

ServicePattern

Constant Variable

Example: Items coming down an automated assembly line.

Example: Items coming down an automated assembly line.

Example: People spending time shopping.

Example: People spending time shopping.

THE QUEUING SYSTEM

Queue Discipline

Length

Number of Lines &Line Structures

Service Time Distribution

Queuing System

EXAMPLES OF LINE STRUCTURES

Single Channel

Multichannel

SinglePhase Multiphase

One-personbarber shop

Car wash

Hospitaladmissions

Bank tellers’windows

ESSENTIAL FEATURES OF QUEUING SYSTEMS

DepartureQueue

discipline

Arrival process

Queueconfiguration

Serviceprocess

Renege

Balk

Callingpopulation

No futureneed for service

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ARRIVAL PROCESS

Static Dynamic

AppointmentsPriceAccept/Reject BalkingReneging

Randomarrivals withconstant rate

Random arrivalrate varying

with time

Facility-controlled

Customer-exercised

control

Arrival process

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QUEUE DISCIPLINE

Queue

discipline

Static(FCFS rule)

Dynamic

selectionbased on status

of queue

Selection basedon individual

customerattributes

Number of customers

waitingRound robin Priority Preemptive

Processing timeof customers

(SPT or cµ rule)12-14

WAITING LINE SYSTEMIncludes the customer population source as well as the process or service system.QUEUING SYSTEMAnother name to define a waiting line.

FINITE CUSTOMER POPULATIONThe number of potential new customers is affected by the number of customers alreadyin the system.

DEGREE OF PATIENCE

No Way!

BALK

No Way!

RENEG

INFINITE CUSTOMER POPULATIONThe number of potential new customers is not affected by the number of customers already in the system.BALKINGThe customer decides not to enter the waiting line.

RENEGINGThe customer enters the line but decides to exit before being served.

JOCKEYINGThe customer enters one line and then switches to a different line in an effort to reduce the waiting time.

THE NUMBER OF WAITING LINES

THE NUMBER OF SERVERS

THE ARRANGEMENT OF THE SERVERS

ARRIVAL AND SERVICE PATTERNSArrival rateThe average number of customers arriving per time period.

Service rateThe average number of customers that can be served per time period.

Waiting Line Priority Rules Generally customers consider first-come, first-served to be the fairest method for determining priority. Other rules include best Customers first, highest profit customer first, quickest service requirement first, largest service requirement first, emergencies first...

CRITERIA FOR SEGMENTATION AND ALLOCATION OF QUEUING POPULATION

Urgency of jobemergencies vs. non-emergencies

Duration of service transactionnumber of items to transactcomplexity of task

Payment of premium priceFirst class vs. economy

Importance of customerfrequent users/loyal customers vs. others

WAITING LINE PERFORMANCE MEASURES

1.The average number of customers waiting in line and in the system.

2. The average time customers spend waiting, and the average time a customer spends in the system.

3. The system utilization rate.

BENEFITS OF A RESERVATIONS SYSTEMControls and smoothes demandPre-sells serviceInforms and educates customers in advance of arrival

Customers avoid waiting in line for service (if service times are honored)

Data capture helps organizations prepare financial projections

CHARACTERISTICS OF WELL-DESIGNED RESERVATIONS

SYSTEMSFast and easy for customers and staffCan answer customers’ questionsOffers options for self service (e.g. Web)Accommodates preferences (e.g., room

with view)Deflects demand from unavailable first

choices to alternative times and locationsIncludes strategies for no-shows and

overbookingrequired deposits discourage no-showsunpaid bookings canceled after designated time

compensation for victims of over-booking

CHANGING OPERATIONAL CHARACTERISTICSCustomer arrival rates.

Number and type of service facilities.

Changing the number of phases.

Server efficiency.

Changing the priority rule.

Changing the number of lines.

THANK YOU