LEAN SIX SIGMA IN CASE STUDIES 1
Lean Six Sigma in Case Studies
Richard S. Stainback Jr.
School of Business, Liberty University
LEAN SIX SIGMA IN CASE STUDIES 2
Abstract
This paper is designed to explore lean thinking and lean six sigma (LSS) as processes for
continuous improvement in organizations. This is accomplished through a comparison of the two
processes from the standpoint of benefits, principles, composition, and purpose. DMAIC is also
discussed as the preferred methodology for the implementation of LSS. The application of LSS
is synthesized across several research outlets and organization demographics. The benefits
outlined in this document include culture creation, waste elimination, and customer experience
improvement. Further offering a biblical viewpoint for waste elimination and continuous
improvement. Finally calling for future research to improve the tools like VSM and WID and to
narrow the scope of application to industry specific subsets.
Keywords: Lean Six Sigma, Lean Thinking, Continuous Improvement, DMAIC
LEAN SIX SIGMA IN CASE STUDIES 3
Lean Six Sigma in Case Studies
The purpose of this paper is to discuss LSS and lean thinking. This will be accomplished
by assessing the differences between LSS and lean thinking, detailing the benefits of LSS,
differentiating between the principles of LSS and lean thinking, exploring DMAIC (Define,
Measure, Analyze, Improve, and Control), and the application of LSS in research. LSS and lean
thinking are tools designed for continuous improvement in organizations designed to create a
lean thinking culture (Sa et al., 2020; Sreedharan V. et al., 2018).
Lean Six Sigma and Lean Thinking
Alblooshi et al. (2020) describes LSS as a methodology for increasing customer service,
reducing cost, and eliminating waste in processes. Six sigma (SS) was originally utilized by
Motorola in the 1980s, SS became more widespread in 1995 used by organizations globally to
create efficiencies. According to Haung (2023) lean thinking originated in the 1950’s as a
methodology implemented by Toyota Production Systems. Lean thinking focuses on people as
the driver of continuous improvement, thus creating a cultural approach in an organization. LSS
is a combination of lean thinking principles coupled with SS statistical methodologies. LSS is a
popular method of obtaining competitive advantage in the more complex markets. The overall
goal of LSS is to reduce defect rates to 3.4 units per million opportunities. Singh et al. (2019)
suggests that lean thinking is a byproduct that remains after the implementation of LSS tools and
processes like value stream mapping (VSM) and waste identification diagrams (WID).
Sa et al. (2020) further stresses the importance of LSS and other continuous improvement
tools as a necessity for implementing a quality management system for organizational
improvement. Sreedharan V. et al. (2018) details the continuous improvement measures like LSS
as a companywide immersion leading to a lean thinking culture. Since the inception of LSS,
LEAN SIX SIGMA IN CASE STUDIES 4
there have been countless different methods of continuous improvement utilized; typically
applied individually with results being analyzed for efficacy. These individual tools may not
solve all the organizational issues and may require the use of more than one tool to identify and
rectify the organization’s problems and institute lean thinking in the organization.
Benefits of Lean Six Sigma
McDermott et al. (2022) outlines several benefits of LSS in the healthcare field including
increased production, reduced waste, error reduction, increased customer experience, and culture
improvement. These benefits can be achieved in a multitude of industries including production,
retail, service-based industries, technology, and manufacturing. This research will focus on
increased customer experience, culture creation, and waste reduction as three key benefits of
LSS.
Customer Experience
George et al. (2005) references the voice of the customer (VOC) as a key component of
the LSS implementation process. The VOC data can be acquired through face-to-face interviews,
satisfaction surveys, Kano analysis, or third-party research data like the National Performance
Dashboard. The purpose of this data acquisition is to identify what the customer finds important
so the organization can focus on these activities and eliminate nonvalue-added activities.
McDermott et al. (2022) aligns organizational competitive advantage with LSS implementation
and increased patient satisfaction, noting that these activities increase productivity and profits for
the organization.
Waste Reduction
According to Asif (2019), lean originally did not focus on waste elimination. Waste
elimination was a benefit of the statistical approach of SS. Furthermore, pointing out that the
LEAN SIX SIGMA IN CASE STUDIES 5
combination of lean and SS to create LSS offers a more complete methodology for sustainable
waste elimination. Proverbs 18:9 states, “Whoever is slack in his work is a brother to him who
destroys” (Holy Bible: New International Version 1973/2011). This verse clearly aligns with the
waste in an organization and its ability to destroy an organization if left unchecked. Siregar et al.
(2019) offers that tools like the value stream map (VSM) are essential tools in identifying areas
of waste in organizational processes. VSMs offer a starting point for identification and should be
updated as changes are made to assess the new state of the process. Dinis-Carvalho et al. (2019)
details another method of identifying waste in the LSS process; the waste identification diagram
(WID). The VSM is and has been the most widely used method of identifying waste, however
the VSM has limitations in speed and interpretation. The WID is specifically designed to
decrease the time needed and accuracy to identify and eliminate waste. Waste elimination
benefits organizations by reducing cost, increasing production, increasing morale, and increasing
customer satisfaction (McDermott et al., 2022; Sa et al., 2020; Singh et al., 2019).
Culture Creation
Sa et al. (2020) points out that the lean part of LSS is derived from the combination of
lean thinking and SS. This combination plays a pivotal role in culture creation in an organization.
As organizations implement LSS principles and processes it is important for the organization to
understand and continually implement the solutions provided. Organizations benefit from a lean
culture that will identify new opportunities organically and before they become a widespread
issue for the organization. McDermott et al. (2022) notes that in healthcare applications
employee satisfaction was increased along with morale. It is imperative to understand that people
are the main form of competitive advantage for organizations and the one thing that cannot be
LEAN SIX SIGMA IN CASE STUDIES 6
copied (Nayak et al., 2022). Alblooshi et al. (2020) noted that the application of LSS in
organizations fosters human capital learning and improves employee satisfaction.
Principles of Lean and Lean Six Sigma
Mentioned previously, Sa et al. (2020) determined that the lean process and LSS share
many similarities in foundations derived from LSS being an integration of lean principles into SS
processes. This combination offers organizations a holistic view of the operation and better
resolve for continuous improvement.
Principles of Lean
Sreedharan V. et al. (2018) outlines continuous improvement as paramount in
organizational success and a key principle of lean thinking and lean manufacturing. Continuous
improvement allows organizations to create competitive advantage by internally executing at a
higher level to reduce cost and waste. The Holy Bible offers guidance on continuous
improvement in Romans 12:2, “Do not be conformed to this world, but be transformed by the
renewal of your mind, that by testing you may discern what is the will of God, what is good and
acceptable and perfect” (Holy Bible: New International Version 1973/2011).This verse
commands us to continually test ourselves to improve in our walk with God. Another key
principle of lean is to identify value, Dinis-Carvalho et al. (2019) suggests that the VSM and
WID are key tools that may be utilized to identify value through the reduction of waste. George
et al. (2005) refers to the VOC as another method of identifying value.
Principles of Lean Six Sigma
Sreedharan et al. (2018) notes that continuous improvement is a principle of both lean
and LSS. Another principle of LSS is value creation, discussed by Dinis-Carvalho et al. (2019) in
the VSM process. According to George et al. (2005) VSM is used in the beginning to identify
LEAN SIX SIGMA IN CASE STUDIES 7
waste and the to-be VSM is used later in the DMAIC process to identify areas of value creation.
Another principle of LSS is waste elimination. Huang et al. (2023) relays that waste elimination
is a key principle of LSS to facilitate process improvement and increase productivity and
profitability.
DMAIC
George et al. (2005) describes DMAIC as the LSS methodology used to identify
problems, determining root causes, offering solutions, and implementing improvements that can
be sustained by the end user. DMAIC incorporates the tools and principles of LSS discussed
earlier to eliminate waste and strive towards organizational excellence. The process can take as
little as a week, with the application of the Kaizen DMAIC approach, or two to four months
dependent on the complexity of the problem. Because of the immensity of this resource
investment, George et al. (2005) is very clear that in some cases the processes are too broken,
and the organization should start over. It is imperative to note that DMAIC cannot solve all
issues in an organization.
George et al. (2005) offers five distinct steps to DMAIC: define, measure, analyze,
improve and control. Each one of these steps must be followed to discover sustainable solutions
to organizational problems. Define is used to validate the problem and create a VSM to address
the problems. Measure is used to identify data collection points and data collection methods
based off a more in-depth VSM. Analyze is the process of applying statistical methods to the
data collected to determine the feasibility of solutions and prepare for the improvement stage.
Improve is the actual process of applying proposed solutions to existing processes to determine
efficacy and desired results. Control is the actual implementation of proven solutions that are
then turned over to the end user.
LEAN SIX SIGMA IN CASE STUDIES 8
Application of Lean Six Sigma Through All Types of Research
George et al. (2005) applies DMAIC as the main method for implementing LSS in
research to solve organizational problems. The DMAIC process allows for both quantitative and
qualitative methods to be deployed throughout the process to determine solutions. The define
phase may use surveys or interviews to aid in determining the problems that need addressed. The
data collection phase uses statistical methods and qualitative methods to improve processes and
attain key value determinations from end users. McDermott et al. (2022) details the prominent
use of LSS in the healthcare field for drug trials, patient care, pharmacy accuracy and other
pertinent operations. Siregar et al. (2019) researched pesticide production in Japan using LSS
methods. Sa et al. (2020) shows the importance of LSS in research and how it can be applied to
various industries and incorporated into research designed to foster continuous improvement and
organizational excellence.
Conclusion
Lean thinking is people centered processes designed to identify value and reduce waste
(Huang et al., 2023). Alblooshi et al. (2020) describes LSS as a methodology designed to
eliminate waste and improve production and customer service in any industry. Both
methodologies center around continuous improvement methods and organizational excellence
(Sreedharan V. et al., 2018). Lean and LSS share several like principles with the main
differentiator being lean is people focused whereas LSS is people and analytically focused (Sa et
al. 2020). DMAIC is the main methodological tool used to implement LSS and incorporates both
quantitative and qualitative methods in the process (George et al. 2005). This research
recommends further research into LSS that will narrow the scope into industry specific subsets
and improve the tools to adapt efficiencies mandated by the evolving world environment.
LEAN SIX SIGMA IN CASE STUDIES 9
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