Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
Queue System Analysis at Starbucks Stores
Farah Rahmatika and Jasmine Shafa Khairunnisa
Faculty of Engineering, Industrial Engineering
Pembangunan Nasional Veteran Jakarta University
Jalan RS Fatmawati, Pondok Labu, South Jakarta
farahrhmtk27@gmail.com & jasmine.shafa27@gmail.com
Akhmad Nidhom Nurzaman
Lecturer of Industrial Engineering
Faculty of Engineering
Pembangunan Nasional Veteran Jakarta University
Indonesia, South Jakarta
akhmadnidhomuzzaman@upnvj.ac.id
Fitra Lestari
Asosciate Professor, Department of Industrial Engineering
Head of Department of Industrial Engineering
Member, IEOM Indonesia Chapter
Sultan Syarif Kasim State Islamic Unversity, Riau, Indonesia
fitra.lestari@uin-suska.ac.id
Abstract
This case study taken from the Starbucks queue occurred because there was a long queue because there
was only one cashier on duty who also made drinks for one customer. Therefore, the purpose of this study
is to examine and how to reduce long queues by using the FIFO (First In First Out) method so that the
expected results can reduce the number of queues and can streamline time with improvements made to
parallel tasks for baristas and cashiers. With the Proposed System, it is proven to be able to reduce the idle
time of queues at Starbucks outlets with an average reduced time of 1.95 minutes and a maximum waiting
time of 5.3 minutes.
System Simulation, Starbucks, Improvement, Proposed System and Queues
Fitra Lestari is an Associate Professor and Head of the Industrial Engineering Department at Sultan Syarif Kasim
State Islamic University, Indonesia. He finished his PhD project with major area in Supply Chain Management at
Universiti Teknologi Malaysia. He is currently a member of IEOM and has published a number of articles in
international journals about Supply Chain Management, Logistics and Performance Measurement.
Akhmad Nidhom Nurzaman is a Lecturer at Universitas Pembangunan Nasional Veteran Jakarta. He teaches System
Simulation, System Modelling, and so on.
Farah Rahmatika A determined 3rd year industrial engineering student who has passion in Supply Chain
Management and Manufacturing. Has a strong communication and interpersonal skills, as a result from my previous
© IEOM Society International
1919
Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
experiences both in academical and non-academical activities. I also have design skill that I mostly use to support my
works. She currently studying system simulation and data science in leisure time.
Jasmine Shafa Khairunnisa. A determined 3rd year industrial engineering student who has passion in Human
Resources Management. Has a strong communication and interpersonal skills, as a result from my previous
experiences both in academical and non-academical activities. I also have design skill that I mostly use to support my
works. She currently studying system simulation and data science in leisure time.
© IEOM Society International
1920
Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
Preliminary
a. Situation Analysis
Queuing activities often occur in everyday life when you want to wait for service, both in the industrial or
service sectors. Queuing occurs when the number of customer arrivals is not balanced with the available service
capacity so that customers cannot be served directly. Every manufacturing or service company is required to
always be able to provide fast service to its customers so that there is no long waiting time. In line with the rapid
changes in the business environment and technology, organizations are also required to make changes for the
better. The development of the food and beverage industry at this time has grown very rapidly. The food and
beverage industry is still the mainstay for Indonesia's economic growth and was able to grow by 8.41% in 2018.
Starbucks Corporation is an American coffee shop chain headquartered in Seattle, Washington. Starbucks is the
world's largest premium coffee roaster-retail company with 22,519 stores in 67 countries. Starbucks sells hot and
cold drinks (espresso, frappucino, smoothies, tea), merchandise (glasses, tumblers, coffee beans), and food
(sandwiches, salads, cakes). Since its founding in 1971 in Seattle, Starbucks has expanded rapidly. Starbucks
entered Indonesia for the first time in 2002 and was operated by PT. Sari Coffee Indonesia which is a subsidiary
of PT. Mitra Adi Perkasa Tbk, as the sole right holder to introduce and market Starbucks in Indonesia. Based on
data from CNN Indonesia (2014), Starbucks has 188 outlets throughout Indonesia.In providing services, the main
problem that often occurs is queuing activities that cannot be avoided, the length of time queuing and the length
of the queue make customers uncomfortable and bored because they feel that time is wasted just to buy this drink
so that it can result in losing customers The average number of queues that occur every day ranges from 8-10
people. The object of this research is the Starbucks SuperMall Karawaci outlet, Tangerang.
b. System Problem
customers come
customer in queue
ordering
Making order
Order complete
Figure 1. Problem in actual system
One of the main issues observed in relation to queues at Starbucks outlets is the accumulation of
queues at the ordering section. It is necessary to look at the level of performance and service of Starbucks
outlets with indicators such as the average service time in the system and the percentage of use of port
facilities to the demand for loading and unloading of goods over a certain period of time.
c.
Simulation Goal
The purpose of this research is to find out the queuing system and the level of service facilities at
Starbuks outlets through a queuing model approach with simulation completion. Meanwhile, the purpose of
this study can be described or described as follows:
i.
Simulating the level of facility performance at Starbucks outlets through a queuing model approach with
simulation completion. These indicators are arrival rate, service level, waiting time or delay, idle or idle
time, and system time.
© IEOM Society International
1921
Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
ii. Identify the need for additional facilities at Starbucks outlets.
d. Limitations and Assumptions
In the process of queuing at Starbucks outlets, the input to be served is orders from customers by
operator1 (cashier-barista) from the ordering process to the finished order output. If there are 2 baristas and
both of them are in the process of making/preparing food or drinks, then the cashier will be idle and the queue
will be long.
In the simulation process this time requires several variables, due to time constraints and situations
we use secondary data so that we use the assumption that in a day per shift there are only 2 baristas. The
service system under study is only focused on the queues that occur and their outputs.
© IEOM Society International
1922
Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
System Modeling
a. Entity=
An entity has a unique and distinct existence, although not necessarily in a physical form. Abstraction, for
example, is usually considered as an entity. In system development, entities are used as models that describe
internal communications and processing, such as distinguishing documents from order processing.
i. Description of Interacting Entities
In the line in store the interacting entities are Buyers Come - Buyers Queued - Buyer Service - Service by
baristas - Order Complete.
b. Activities/Relationship
A relation is a rule that pairs the members of one set to another. We can find relations in mathematics lessons,
such as relations from set A to set B. The relation in question is the installation or correspondence of members of
set A to set B.
i. Relationship Diagram
Figure 2. Relationship Diagram Starbucks System
© IEOM Society International
1923
Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
c. Resources
The resources in this outlet are divided into 2. The first source is the resource where this Starbucks outlet
employs waiters, baristas, store managers. At the same time, the second source is the ingredients for making food
or drinks taken from factories or agricultural fields
i. Server/Service Unit Description
The service unit at Starbucks outlets is a cashier who doubles as a barista, each customer has one waiter who
serves from the beginning to the delivery of products to customers.
d. Entity Flow Diagrams (EFD)
Entity Flow Diagram is a diagram that connects between entities, this EFD is one type of structural diagram
that is commonly used and utilized in the design of a database or business plan.
COME
0
ORDER
MAKE
0
0
COMPLETE
0
e. Activity Cycle Diagram (ACD)
Customer
Come
Customer
In Queue
Making
Order
Serving
Customer
Idle
Service
© IEOM Society International
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Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
Data collection
a. Data source
i. Data Structure
Interview
Actual Data
Live
research
Operational
Data Store
Data
Warehouse
Improvement
Proposal
Indirect research
Figure 3. Data Structure at Starbucks
ii. Operational Data
Starbucks
Outlet
Drive Thru
In Store
Sales data in a day
Sales data in a day
Transaction data in a day
Transaction data in a day
Average queue time
Average queue time
Figure 4. Optional Data at Starbucks
© IEOM Society International
1925
Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
iii. Numerical Data
Table 1. Time of Service and Service Provider
Number of
Customers
1
Service
Provider
1
2
1
245
3
1
345
4
1
435
5
1
454
6
1
212
7
1
334
8
1
333
9
1
321
10
1
333
11
1
432
12
1
332
13
1
132
14
1
332
15
1
333
16
1
232
17
1
432
18
1
421
19
1
312
20
1
363
21
1
394
22
1
367
23
1
365
24
1
309
25
1
356
26
1
351
27
1
378
Service Time (Second)
Average
234
336.5555556
b. Method of collecting data
i. Interview
Interviews were conducted directly with workers at Starbucks outlets, the questions we asked were
as follows:
•
What is the average number of customers coming in one week?
•
What is the average amount of service time?
© IEOM Society International
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Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
•
How do managers assess service performance?
c. Data analysis
Data analysis was carried out for making simulations in the form of models using Arena software. The first
stage is the buyer arrives. After the buyer arrives, then proceed with queuing first if there is a queue, followed by
ordering according to the desired menu to the cashier or waiter at the Starbucks outlet. After the service is
complete and the payment has been made, the customer must wait because the waiter is processing the order, and
if the order has been processed, the order is ready to be taken by the customer.
© IEOM Society International
1927
Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
Input and Output Analysis
a. Model Translation in ARENA
i. Before Reconstruction
Figure 5. Table When Buyers Come to Starbucks
Buyers come to Starbucks outlets to carry out the process directly.
Figure 6. Customer make the order
Then the customer makes the order process at the cashier.
© IEOM Society International
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Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
Figure 7. Ordering Process
After the ordering process is done, the operator can continue with the ordering process.
Figure 8. Order Complete
If the purchase is complete and the order is complete, the order is complete.
© IEOM Society International
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Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
ii. After Reconstruction
Figure 9. Buyers come to Starbucks outlet
Buyers come to Starbucks outlets and queue according to the order.
Figure 10. Buyer Place An Order
After the buyer queues, the buyer can place an order and the barista can make an order according to the
buyer's request.
© IEOM Society International
1930
Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
Figure 11. Purchase Transaction Complete
After the purchase and manufacture process is complete, the purchase transaction is complete.
b. Verification
Figure 12. No Error Verification
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Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
c. Validation
i. Determination of Performance Matrix
Figure 13. Key Performance Indicators
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Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
Experimentation
a. Actual System
Before reconstructions are made, queuing is carried out and then continuing with the customer ordering the
desired food or drink. After ordering, the operator (barista) makes an order that the customer has ordered. If it is
finished, the customer can take the order; this causes the waiting time in the queue to increase because there is no
operator in the ordering section if both operators are preparing orders. Before repairing, the conditions in the
queue at Starbucks outlets can be quite long because the longest waiting time for ordering occurs in 13.3 minutes,
with an average waiting time of 2.88 minutes.
b. Proposed System
After reconstructions are made, the process is carried out by queuing and then continuing to order. However,
the operator in ordering and manufacturing is different, so there is no queue buildup in ordering. After improving
the conditions that occur in the queue at Starbucks outlets, the number of customers during the replication time is
313 customers per day, and the longest waiting time is 8 minutes with an average of 0.93 minutes.
c. Comparison of Actual and Proposed system
Figure 14. Comparison of Actual and Proposed System
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1933
Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
Conclusion
Starbucks outlets have an inefficient service system which results in long queues so that they have a long idle
time. And the Proposed System by queuing and then proceeding to order, but the operator in the order and in the
manufacture is different. This results in reduced idle time and the Proposed System can be said to be proven to reduce
idle time in the queue.
© IEOM Society International
1934
Proceedings of the Second Asia Pacific International Conference on Industrial Engineering and Operations Management
Surakarta, Indonesia, September 14-16, 2021
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