What is Lean Six Sigma? Key Concepts Explained

Lean Six Sigma and Six Sigma are two widely adopted methodologies in process improvement, each offering unique approaches to enhancing efficiency and reducing waste. While they share a common goal of optimizing performance, the key difference lies in their focus areas. Six Sigma primarily targets minimizing process variability and defects, relying on data-driven analysis and statistical tools. On the other hand, Lean emphasizes eliminating waste, ensuring workflows run at maximum efficiency, and providing value to customers with the lowest possible amount of investment.

Understanding these differences is crucial for organizations looking to implement a process improvement strategy that aligns with their operational needs. Lean Six Sigma, which integrates the principles of Lean and Six Sigma, takes a balanced approach to improving the speed and quality of a process. However, knowing when to apply each methodology—whether focusing on defect reduction or waste elimination—can significantly impact the success of the initiative.

In this blog, we will explore how Lean Six Sigma differs from Six Sigma, exploring its core principles, tools, and methodologies. By the end, you will clearly understand how both approaches work, when to use them, and the advantages they bring to process improvement initiatives.

Key Takeaways:

 Dual Focus on Efficiency and Quality: It combines Lean’s waste elimination with Six Sigma’s defect reduction for efficient, high-quality outcomes.

Customer-Centric Improvements: Lean Six Sigma aligns improvements with customer needs, ensuring changes enhance satisfaction.

Expanded Applicability: Originally developed for manufacturing, Lean Six Sigma is now widely used across industries like healthcare and finance to streamline processes and improve customer satisfaction.

What is Lean Six Sigma?

Lean Six Sigma combines two methodologies: Lean, which is about eliminating waste and inefficiency, and Six Sigma, which uses statistics to identify causes of process variation.

Japanese automaker Toyota codified lean concepts into what became known as the Toyota Production Systemin the 1940s to improve efficiency and eliminate waste from production. Motorola engineer Bill Smith developed Six Sigma in 1986 to boost the organization’s profits by improving product quality through the elimination of defects from any process. Within the first 20 years of its adoption, Motorola saved $17 billion thanks to Six Sigma’s data-driven approach to quality control.

In 2002, Michael George and Robert Lawrence Jr. introduced the combination of Lean and Six Sigma strategies in their book Lean Six Sigma: Combining Six Sigma with Lean Speed. Lean is less rigorous and more visual, often used in manufacturing to optimize processes. Six Sigma, however, is more analytical and focuses on meeting customer specifications using statistical methods to minimize variation and defects. In Lean Six Sigma, these approaches complement each other, with Lean providing immediate, visible benefits and Six Sigma offering a deeper, data-driven analysis for long-term process improvement.

The Foundations of Lean

Although Lean originated from the manufacturing industry, its principles apply to other sectors because its core focus is to maximize customer value while minimizing waste, something every organization strives for regardless of industry.

To better understand how the Lean Six Sigma methodology works, let’s look at a few of the key concepts that serve as its foundation:

Value Stream Mapping (VSM)

This technique visually represents the end-to-end processes in delivering a product or service to a customer. The VSM should include all the necessary people, processes, information, and raw materials and display them in a flowchart format. The VSM helps identify waste, inefficiencies, and areas for improvement in a process. It is a vital tool in Lean methodology for understanding, analyzing, and optimizing the flow of materials and information throughout the entire value stream.

5S: Sort, Set, Shine, Standardize, Sustain

The 5S system is a set of workplace organization and housekeeping principles to create a clean, organized, and efficient work environment. Its purpose is to reduce waste, improve productivity, and enhance safety. This framework, which one could argue is rooted in common sense, consists of five interrelated steps:

• Seiri (Sort): Remove unnecessary items from the workspace and keep only essential items for daily tasks. By clearing out hazardous and unnecessary objects that cause risks and distractions, the goal is to use space more effectively.
• Seiton (Set in Order): Organize and arrange items logically and efficiently for easy access, and then position them based on how frequently you use them. 
• Seiso (Shine): Clean and maintain the work area to ensure a safe and efficient environment.
• Seiketsu (Standardize): Establish standardized work practices and procedures to sustain steps 1-3.
• Shitsuke (Sustain): Develop a culture of continuous improvement and maintain the 5S practices over the long term. Typically, the most challenging step, the Sustain phase, requires training and good communication to ensure that the cost and effort put into 5S are not wasted.

Continuous Improvement

Often referred to as Kaizen, which means “change for better,” the philosophy of making ongoing incremental improvements to processes, products, or services is essential to Lean Six Sigma. Continuous improvement can feel abstract because it is an idea, a mindset, or a pillar of corporate culture. Kaizen is far less structured than most Six Sigma principles, but establishing an environment that promotes continual learning and innovation is necessary to enhance overall performance.

The Principles of Six Sigma

Six Sigma aims to improve and optimize processes by reducing variability and eliminating defects. “Six Sigma” is a statistical measure quantifying how much a process deviates from perfection. Six Sigma’s core is that reducing process variation enhances quality and improves overall performance. Data collection is the key to Six Sigma, as even the most rigorous analysis can lead to incorrect conclusions if the data is inaccurate.

DMAIC

DMAIC (Define, Measure, Analyze, Improve, Control) is the Six Sigma process that improves existing business processes. A DMAIC project consists of the following phases:

• Define: The first stage is identifying the problem, the improvement opportunity, the project goals, and the customer requirements (internal and external). Once the team understands the situation, they must create a map illustrating how they will fix it.
• Measure: With the project map prepared, the team must collect data and quantify the problem. This data allows the project team to measure performance and evaluate improvement.
• Analyze: In this stage, teams use the data to investigate and verify the variables impacting the problem. To determine what is causing a defect at the center of a project, identify the relationships between the variables to understand the cause and effect.
• Improve: At this stage, the team should eliminate the underlying cause of the defect. Doing so requires running experiments to learn how to implement the desired improvements.
• Control: Six Sigma teams must measure performance in the final stage to ensure the newly improved process is successful. If any deviations from the previously targeted improvements are found, correct them. Finally, a quality control plan should be created to explain how to maintain the improved process at its newly achieved level.

Six Sigma is a structured and systematic approach to problem-solving and process improvement. It involves a relentless commitment to data integrity, which allows organizations to make data-driven decisions at every turn.

Combining Lean and Six Sigma

While Lean and Six Sigma are separate methods, it’s common to see organizations combine them because they are proven to complement each other. It is important to remember to use the best methods and tools for each problem.

Real-world examples are often the best way to learn how Lean and Six Sigma can be combined, so here are a few scenarios:

Example 1: Streamlining a Bank’s Loan Approval Processes

A bank was dealing with customer dissatisfaction due to long loan approval times and inconsistent service quality and used Lean and Six Sigma to streamline their process. Using Lean, they identified redundant paperwork and approval steps causing unnecessary delays, eliminating these inefficiencies to reduce overall processing time.

They applied Six Sigma techniques, such as process mapping and root cause analysis, to pinpoint and address errors in data entry and credit evaluation, contributing to inconsistent loan decisions. By combining these methodologies, the bank reduced loan approval times by 40%, improved accuracy, and significantly increased customer satisfaction.

Example 2: Improving Production Delays and Quality Issues

A manufacturing organization was struggling with frequent production delays and quality issues. They combined Lean and Six Sigma methodologies to find and correct the production problems. Using Lean, they first identified bottlenecks in their assembly line and removed unnecessary steps causing delays, significantly speeding up the workflow.

Next, they used Six Sigma tools, such as root cause analysis and statistical process control, to pinpoint and reduce defects in their products. By streamlining the process with Lean and improving quality with Six Sigma, the company reduced production time by 30%. It cut defect rates in half, improving customer satisfaction and cost savings.

Benefits of Lean Six Sigma

The benefits of adopting Lean Six Sigma include:

• Improved product and service quality
• Reduced operational costs
• Enhanced process efficiency
• Greater customer satisfaction

Lean Six Sigma Tools and Techniques

What are the tools that make Lean Six Sigma so effective? Let’s take a look:

Voice of the Customer

Voice of the Customer (VOC) data is gathered through surveys, focus groups, stakeholder interviews, and indirectly through feedback or complaints. This data is then translated into Critical to Quality (CTQ) characteristics, turning customer needs into specific, measurable goals. This approach ensures that all improvements are aligned with customer expectations and requirements.

5 Whys

The 5 Whys is a powerful technique used in the Analyze phase of DMAIC to identify and eliminate the root cause of a problem, by repeatedly asking “Why”—typically five times—you drill down to the underlying issue, continuing until no further answers are possible, ensuring that solutions address the real issue rather than just the symptoms.

Pareto charts

A Pareto chart is a valuable tool for analyzing data on potential root causes or the frequency of issues in a Six Sigma Root Cause Analysis (RCA). Lean Six Sigma professionals use it to prioritize multiple problems and causes, allowing them to focus on the most significant ones that will have the greatest impact on process improvement.

Selecting the right Lean Six Sigma tools for specific projects might seem daunting. The truth is that the answer has a way of presenting itself. You can only choose tools based on the nature of the project, the type of data available, and the specific process improvement objectives.

Success Stories

Let’s learn about organizations that have successfully implemented Lean Six Sigma and how it has positively impacted business performance and competitiveness:

Microsoft

Microsoft applied Lean Six Sigma to improve its Surface tablet production by identifying waste, streamlining workflows, and enhancing quality control. Using Lean Six Sigma led to reduced defects, faster production times, and cost savings, ultimately increasing customer satisfaction and improving manufacturing efficiency.

Xerox

The workplace and digital printing solutions company made a company-wide commitment to Lean Six Sigma, which started in 2003. Over the next ten years, it trained roughly 500 black and 2,500 green belts, who helped deliver expert business process consulting and assessment services to customers. These services saved 35% of customers’ total document costs while optimizing their IT and infrastructure investments.

Challenges and Pitfalls

One of the challenges organizations face is knowing what projects deserve the Lean Six Sigma approach. It’s a common misconception that every process needs to reach a Six Sigma level. Organizations also often need help understanding the rigor and patience required for Lean Six Sigma, especially if there is a lack of leadership buy-in.

To overcome this challenge, you can conduct executive training to help them understand how rigorous Lean Six Sigma is. It’s also important to set realistic expectations and start with small-scale projects to demonstrate the immediate benefits of Lean Six Sigma. Once you can prove the benefits, moving on to more extensive implementations becomes easier.

Conclusion

To successfully implement Lean Six Sigma, you must understand the balance between the rigor of Six Sigma and the more visual and straightforward approach of Lean. You will yield positive results if you can achieve this balance while securing executive buy-in and patience for the methodology. Combining the strengths of both Lean and Six Sigma methodologies creates a powerful framework for process improvement and organizational excellence.