Frontiers in Business, Economics and Management 
ISSN: 2766-824X | Vol. 19, No. 2, 2025 

 

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Sigma in the Service Industry 

Lingling Long * 

School of Economics and Management, Southwest Petroleum University, Chengdu 610500, China 

* Corresponding author: XLLL0039@163.com 

 

Abstract: This paper discusses Six Sigma in the service industry. Firstly, it reviews the Six Sigma theory and its development 
history. Then, it expounds on the connotation of Six Sigma and the current situation of its industrial applications, includin g its 

applications at the theoretical and macro levels. Subsequently, it focuses on the applications of Six Sigma in the service field and 

conducts a comprehensive summary and analysis of two cases. 

Keywords: Six Sigma; Lean; Quality Management; Service Industry. 

 

1. Introduction 

The Six Sigma (6σ) theory originated from Motorola in the 

mid - 1980s. It was put forward as a quality goal pursuing 

customer satisfaction and perfect quality in response to the 

impact of Japanese enterprises, aiming to improve product 

quality and enhance competitiveness. Due to the 

implementation of Six Sigma, Motorola won the Malcolm 

Baldrige National Quality Award in 1988. In 1995, Jack 

Welch, the CEO of General Electric, developed Six Sigma 

into a business strategy to enhance the core competitiveness 

of the enterprise. Subsequently, the successful application of 

Six Sigma in General Electric attracted the attention, 

recognition, and acceptance of world - renowned enterprises, 

including Fortune 500 companies. Multinational companies 

such as Ford, Caterpillar, Dow Chemical, DuPont, ABB, and 

Citibank also successively joined the ranks of implementing 

Six Sigma and achieved remarkable benefits. Since 2000, 

Motorola has proposed the "New Six Sigma Method", a 

change method aiming to enhance organizational 

competitiveness and transform organizational culture. At the 

same time, Six Sigma has gradually developed into a set of 

management concepts and systematic methods that enable 

organizations to maintain continuous improvement, 

strengthen comprehensive leadership, continuously improve 

customer satisfaction, and business performance. Six Sigma 

has formed the scientific problem - solving process DMAIC 

(define, measure, analyze, improve, control) and Design for 

Six Sigma (DFSS). Focusing on customer needs, it achieves 

the goals of reducing process fluctuations, improving quality, 

reducing costs, and optimizing processes through the 

systematic and integrated use of systematic and scientific 

tools, meeting and exceeding customer expectations [1]. Six 

Sigma is often combined with lean management to form Lean 

Six Sigma (LSS). 

2. Six Sigma and Its Industrial 
Applications 

2.1. The Core Principles of Six Sigma 

Six Sigma is a data - based management approach. It 

improves the efficiency and quality of production processes 

by reducing variability and the number of defective products. 

With features such as data - driven quality improvement, 

emphasis on process stability and controllability, increasing 

production efficiency and reducing costs, and promoting 

continuous organizational improvement, it has a significant 

impact on the field of quality management. It helps 

organizations enhance product quality, cut costs, and boost 

competitiveness. 

‘σ’ is a Greek letter. In statistics, it is used to represent the 

standard deviation value, which describes the degree of 

deviation of individuals in the population from the mean. The 

measured σ represents probabilities such as the number of 

defects per unit, defects per million, or errors. The larger the 

σ value, the fewer the defects or errors. 6σ is a goal. This 

quality level means that 99.99966% of all processes and 

results are defect - free. That is to say, for every one million 

things done, only 3.4 are defective, which is almost 

approaching the most perfect state that humans can achieve 

[2]. 

The quality management principles of Six Sigma can be 

briefly summarized as follows: 

Customer - centric:  

Understand and meet customer needs, provide high - 

quality products and services, and win customer trust and 

loyalty. 

Management based on data and facts: 

 Make objective and accurate management decisions by 

collecting and analyzing data, avoiding subjective 

assumptions and biases. 

Emphasis on process improvement:  

Optimize key processes, improve efficiency and reliability, 

reduce costs, and achieve excellent quality and customer 

satisfaction. 

Prevention - oriented:  

Focus on preventive quality improvement, identify and 

solve problems early to avoid bigger problems and costs later. 

Boundary - less cooperation:  

Promote cross - departmental and cross - level 

communication and collaboration to jointly solve complex 

problems and achieve better performance and innovation. 

Continuous improvement and innovation:  

Continuously challenge the status quo, seek opportunities 

for improvement, introduce new products and services, and 

improve quality and performance. 

2.2. The Methods of Six Sigma 

The DMAIC in the Six Sigma method is a systematic 

approach for problem - solving and process improvement. It 

provides a systematic framework for problem - solving and 



 

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process improvement, helping organizations effectively 

identify problems, analyze data, and continuously improve 

and control processes, thus achieving continuous 

enhancement of quality and performance.  This 

approach consists of five key steps: 

Define:  

In this stage, the team needs to clearly define the problem 

statement, project goals, key performance indicators, etc. This 

helps ensure that all team members have a consistent 

understanding of the problem, laying the foundation for 

subsequent work. The focus of this stage is to clarify the scope 

and impact of the problem, providing a basis for subsequent 

analysis and improvement work. 

Measure:  

In this stage, the team will start collecting data to analyze 

the current situation of the process or problem, providing an 

objective basis for future improvement work. The 

measurement stage usually includes determining the data - 

collection method, collecting and organizing data, and 

verifying the accuracy and reliability of the data. 

Analyze:  

In the analysis stage, the team will dig deep into the data, 

seek the root causes of the problem, and identify potential 

improvement opportunities. By using statistical tools and 

techniques, the team can identify specific factors causing the 

problem and the extent of their impact on performance. This 

is helpful for formulating targeted improvement plans. 

Improve: In this stage, the team will develop and 

implement improvement measures based on the previous 

analysis results. This may involve designing new processes, 

adjusting existing processes, introducing new technologies or 

methods, etc. The goal of the improvement stage is to 

eliminate defects, increase efficiency, and meet customer 

needs. 

Control:  

In the control stage, the team will ensure that the 

improvements are continuously applied and produce the 

expected results. This may include establishing monitoring 

mechanisms, developing standard operating procedures, 

training relevant personnel, etc. Through the work in the 

control stage, the team can ensure the continuous 

effectiveness of the improvements. 

2.3. Six Sigma in Different Industries 

In the past decade, the application of Six Sigma 

management in the field of nursing quality in China has been 

developing steadily, significantly improving nursing quality, 

work efficiency, patient safety, and nurse satisfaction [3]. 

Trakulsunti et al. explored the applicability of Lean Six 

Sigma in the medical industry and proposed a path to improve 

the quality of medical services and patient satisfaction with 

the concept of Lean Six Sigma [4]. In recent years, the 

application of Lean Six Sigma in the medical field has 

received much attention, and the number of academic papers 

published has increased rapidly, such as reducing patient 

waiting times and improving the quality of surgeries. Many 

hospitals in China have also started to implement Lean Six 

Sigma, which plays an important role in optimizing the 

medical service process, enhancing the quality of medical 

services, and increasing patient satisfaction. 

Zhao Xiaosong et al. reviewed the application research of 

Six Sigma in software process measurement, emphasizing the 

importance of Six Sigma in improving existing processes and 

controlling product design quality [5]. 

Six Sigma can also be used in corporate cost management. 

Chopra (2012) [6] proposed that quality cost management 

requires companies to manage quality and cost in an 

integrated manner. The relationship between cost and quality 

management is multi - faceted. Product quality is not the only 

factor affecting a company's efficiency; it also depends on 

whether the company can adjust the boundaries of cost 

control at the appropriate time. 

Yang Erhao et al. [7] studied the application of the DMAIC 

method of the Six Sigma quality management model in the 

total assembly quality control of military aircraft engines. By 

optimizing the installation process and formulating a detailed 

control plan, they successfully increased the first - pass 

qualification rate of engine installation, reduced production 

process variation, and improved production efficiency. 

Yang Chi et al. [8] reviewed its typical applications in the 

shipbuilding field, pointed out the main problems currently 

existing in ship applications, such as the low utilization rate 

of single innovative methods and the lack of integrated 

applications of multiple innovative methods. In response to 

the problems in the shipbuilding field, they proposed an 

innovative integration framework based on Six Sigma and 

other innovative methods in the shipbuilding field. 

3. Six Sigma in the Service Field 

Today, the enthusiasm for Six Sigma remains undiminished. 

Its application scope has long transcended the manufacturing 

industry and expanded to service industries such as finance, 

healthcare, and education. 

The service industry, as an economic sector mainly 

providing various services, has many characteristics. These 

include intangibility and heterogeneity, high interactivity and 

variability, expansibility and employment - generating 

capacity. It also features knowledge - intensity and 

dependence. However, the service industry also faces a series 

of challenges. These include difficulties in ensuring service 

quality, high labor - cost pressure, fierce market competition, 

as well as increased information asymmetry and reputation 

risks. Therefore, during the development process, the service 

industry needs to continuously increase investment in 

management innovation, technological innovation, and talent 

cultivation to enhance service quality and competitiveness, 

address various challenges, and achieve sustainable 

development. 

The financial services division of General Electric 

Company (GE) achieved remarkable success when promoting 

the Six Sigma methodology. By applying the Six Sigma 

approach, they significantly improved the efficiency and 

accuracy of customer service and reduced processing times. 

This also enabled them to stand out in the highly competitive 

financial services market.  Motorola began introducing 

Six Sigma into its customer service center in the early 1990s. 

Through process improvement, operation simplification, and 

enhanced training, Motorola significantly improved customer 

service quality, while reducing customer complaints and 

return rates, winning more market share and customer trust 

for the company. In the banking industry, many institutions 

apply Six Sigma in risk control and loan approval. Through 

refined data analysis and process optimization, banks can 

more accurately assess customer credit, reduce the bad - debt 

rate, and lower risks while improving the efficiency of loan 

approval. 

This chapter will introduce several classic cases of the 

application of Six Sigma in the service field. 



 

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3.1. Practice of Outpatient Service Process 
Optimization Based on Lean Six Sigma 

Management [9] 

This exploration focused on the effects of Lean Six Sigma 

management in optimizing the outpatient service process of 

general hospitals. By comparing the data of the observation 

group and the control group, it was found that the adoption of 

Lean Six Sigma management could significantly reduce the 

visiting time, waiting time, and medicine - collection time of 

outpatient patients, and at the same time, increase patient 

satisfaction. The conclusion pointed out that the outpatient 

service process based on Lean Six Sigma management 

achieved good improvement results, providing general 

hospitals with a set of outpatient service optimization 

processes that could be promoted and used for reference. 

Define:  

A DMAIC management team was established, led by the 

director of the outpatient department. Through professional 

training and literature review, the current medical treatment 

situation and needs of outpatient patients were summarized, 

and the key nodes of outpatient management were determined. 

Measure:  

The value - stream analysis method was used. Data was 

retrieved from the hospital's outpatient patient database, and 

a value - stream map was drawn to analyze the unnecessary 

time consumption in the medical treatment process. 

(3) Analyze:  

Through questionnaires, patients' medical treatment needs 

and the current situation were understood, values were 

determined, and the aspects that needed improvement were 

identified. 

(4) Improve:  

A series of measures were implemented, such as enabling 

thermal - imaging automatic temperature - measuring 

equipment, carrying out time - segmented appointment 

registration, and promoting the construction of Internet - 

based hospitals, etc., to reduce patients' waiting time and 

improve service efficiency. 

(5) Control:  

Through the feedback of patient satisfaction surveys, the 

service quality was continuously improved, and the overall 

patient medical treatment experience was enhanced. 

The comparison of data between the control group and the 

observation group showed that the visiting time, waiting time, 

and medicine - collection time of outpatient patients in the 

observation group were significantly shorter than those in the 

control group, and the patient satisfaction was higher than that 

in the control group. The difference was statistically 

significant (P < 0.05). 

The optimization of the outpatient service process 

significantly reduced patients' visiting time and waiting time 

and increased patient satisfaction. This indicates that the 

application of Lean Six Sigma management effectively 

optimized the outpatient service process, improved service 

quality, and enhanced the patient experience. The evaluation 

of the optimization effect of the outpatient service process 

based on Lean Six Sigma management is positive. Through 

the implementation of Lean Six Sigma management, the 

outpatient service process has been significantly optimized, 

patient satisfaction has increased, and a set of outpatient 

service optimization processes suitable for promotion and 

reference in general hospitals has been formed. 

The practical significance of this research lies in providing 

an effective management method to optimize the outpatient 

service process, improve the patient medical treatment 

experience, and enhance the efficiency of medical services. 

Its promotional value lies in that this method can be borrowed 

and applied by other hospitals to improve the service quality 

and efficiency of the entire medical industry. 

3.2. Research on Improving the Quality of 
Automobile Sales Service Based on Six 

Sigma [10] 

This thesis studies how to improve the quality of 

automobile sales service through the Six Sigma management 

method. Taking an X automobile 4S store as the research 

object, it analyzes the key factors affecting the sales service 

quality and proposes improvement measures. The research 

results can provide a theoretical basis for automobile 

companies to improve their sales service levels. 

In this case, the Six Sigma method, through its five steps - 

Define, Measure, Analyze, Improve, and Control, helps the 

automobile company systematically identify and solve 

problems in sales services, thus improving the sales service 

level. Specifically: 

Define:  

Identify the issues that customers care about most, such as 

dissatisfaction points in sales services, as the improvement 

targets. 

Measure:  

Collect data to quantify the performance of sales services, 

such as customer satisfaction, service response time, etc. 

Analyze:  

Analyze the sales service process to find out the key factors 

affecting service quality, such as the communication skills of 

sales staff and the efficiency of the service process. 

The key factors include:1. Pre - sales service: Such as 

telephone invitations, preparation of test - drive cars, cleaning 

of exhibition cars, etc.2. In - sales service: Such as vehicle 

grooming and relevant services according to customers' 

personalized needs.3. Communication skills and service 

attitude of sales staff: Including patience and sincerity when 

answering customers' calls, as well as the consistency 

between verbal promises and actual services during the sales 

process.4. Compliance in the sales process: Such as avoiding 

behaviors that may lead to disputes, like forced insurance 

sales, bundling of automobile decoration projects, forced 

agency for license - plate registration, and charging of 

mortgage handling fees. 

Improve: 

 Based on the analysis results, formulate improvement 

measures, such as training sales staff, optimizing the service 

process, etc. 

Control:  

Through continuous monitoring and adjustment, ensure 

that the improvement measures are maintained and prevent 

problems from occurring again. Control the service quality 

through efforts in enhancing the professionalism of sales 

consultants and providing personalized services. 

4. Summary  

This paper briefly reviews the applications of Six Sigma in 

the service field. It introduces the connotation of Six Sigma 

and its functions in fields such as manufacturing and finance. 

Then, it presents the applications of Six Sigma in the service 

field through two relatively new cases. 



 

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Looking ahead, with the continuous development of the 

service industry and the improvement of the Six Sigma theory, 

the application of Six Sigma in the service industry will 

become more in - depth and extensive. It is hoped that future 

research will pay more attention to the practical applications 

of Six Sigma in the service industry, propose more specific 

and effective methods and strategies, and provide more 

powerful support for the continuous improvement and 

innovation of the service industry. 

References 

[1] He Zhen, Hu Hao, Liu Hailong, et al. Review of Theoretical 
Research and Application of Lean Six Sigma [J]. Industrial 
Engineering, 2021, 24(05): 1 - 8 + 54. 

[2] Chen Xue. Six Sigma [J]. Chinese Nursing Management, 2020, 
20(9): 1291. 

[3] Zhu Juanfang, Shen Wangyuan, Chen Shiqi, et al. Analysis of 
the Application of Six Sigma Management in the Field of 
Nursing Quality in China from 2012 - 2021 [J]. Chinese 
Hospitals, 2023, 27: 87 - 90. 

[4] Trakulsunti Y, Antony J, Douglas J A. Lean Six Sigma 
implementation and sustainability roadmap for reducing 
medication errors in hospitals [J]. The TQM journal, 2020, 
33(1): 33 - 55. 

[5] Zhao Xiaosong, He Zhen, Gui Fangfang, et al. Review of the 
Application of Six Sigma in Software Process Measurement [J]. 
Computer Engineering and Applications, 2007(22): 6 - 9. 

[6] Chopra, Garg A. Introducing models for implementing cost of 
quality system [J]. The TQM journal, 2012, 24(6): 23 - 27. 

[7] Yang Erhao, Liu Yusong, Huang Jichuan. Application of Six 
Sigma in the Total Assembly Quality Control of Military 
Aircraft Engines [J]. Hangkong Gongcheng Jinzhan, 2023, 
14(03): 138 - 145. 

[8] Yang Chi, Zhou Feihong, Li Shougen, et al. Research on the 
Application of Six Sigma in the Ship Field [J]. Journal of 
Beijing Institute of Petro - Chemical Technology, 2024, 32(01): 
6 - 11. 

[9] Zhang Cheng, Xu Jie, Li Chunyu, et al. Practice of Outpatient 
Service Process Optimization Based on Lean Six Sigma 
Management [J]. Chinese Hospital Management, 2021, 41(04): 
65 - 68. 

[10] Yang Peijuan. Research on Improving the Quality of 
Automobile Sales Service Based on Six Sigma [J]. [Publication 
details not fully given], 2024(02): 110 - 112.