Lean and Six Sigma differ in their respective approaches to process improvement. While both systems aim to reduce waste, streamline processes, and improve efficiency, their key approaches and outcomes differ.
Lean and Six Sigma have strengths and weaknesses and can be used in different contexts to improve processes. Lean is best suited for reducing lead time and improving efficiency, while Six Sigma is best suited for reducing variation and improving quality.
What is Lean?
Lean is a philosophy and set of tools for process improvement originally developed by Henry Ford to make automobiles. It was later adopted and expanded by Toyota in Japan into the Toyota Production System (TPS).
Lean quality eliminates waste, reduces lead time, and improves process efficiency. Lean TPS emphasizes continuous improvement, quality at the source, and customer satisfaction.
Lean improves processes by eliminating eight forms of waste: defects, overproduction, waiting, motion, transport, inventory, over-processing, and underutilized people. The primary goal of Lean is to reduce lead time by removing these non-value-adding activities or waste.
It emphasizes streamlining processes and eliminating activities that do not add value to the customer experience. Lean is best suited for companies that must reduce costs and improve customer satisfaction.
Value stream mapping, 5S, and Kanban are examples of Lean tools. Toyota’s Just-in-Time system eliminates waste and reduces lead time by supplying the right number of parts at the right time.
What is Six Sigma?
Six Sigma is a process improvement system developed in the U.S. that focuses on reducing defects and improving customer satisfaction. Six Sigma is based on the Define-Measure-Analyze-Improve-Control (DMAIC) model and emphasizes problem-solving and data-driven decision-making. The primary goal of Six Sigma is to reduce process variation and improve customer satisfaction by reducing defects and increasing quality.
The result is to achieve a high level of performance by minimizing errors and improving customer satisfaction. Using statistical analysis and data-driven approaches, Six Sigma aims to identify and eliminate problems, improving overall performance and cost savings.
An example of Six Sigma in action is Intel’s use of Six Sigma to reduce defects and improve customer satisfaction by measuring and analyzing the performance of its processes. Other Examples of Six Sigma process improvement:
- Manufacturing: A company wants to reduce the number of defective products by identifying and eliminating the root causes of defects in its production line.
- Healthcare: A hospital aims to decrease patient wait times in the emergency room by analyzing the process flow and implementing improvements based on data-driven insights.
- Customer Service: A call center seeks to enhance customer satisfaction by reducing the average handling time of customer inquiries and addressing recurring issues.
- Financial Services: A bank aims to improve the accuracy and efficiency of its loan approval process by identifying bottlenecks and streamlining the workflow.
- Supply Chain: A logistics company wants to minimize delivery delays and optimize inventory levels by identifying and mitigating factors causing disruptions in the supply chain.
- Software Development: A software company aims to reduce the number of software bugs by implementing rigorous testing processes and analyzing patterns in defect occurrence.
In all these examples, Six Sigma principles and tools, such as DMAIC, identify problem areas, collect and analyze data, propose improvements, and monitor the results to ensure sustained improvements over time.
Difference Between Lean and Six Sigma
Lean and Six Sigma are distinct process improvement systems with different approaches and goals. Lean is technically simple, utilizing little math, but it is culturally complex because of its systemic orientation and paradigm shift in thinking. Lean is about increasing process flow by eliminating waste.
Six Sigma is technically complex, utilizing data and statistics to determine the best action. It is culturally simple and can be taught project-by-project or group-by-group. Six Sigma is about reducing variation by removing the causes of variation to improve performance.
Lean focuses on reducing lead time and eliminating waste, while Six Sigma focuses on reducing variation and improving quality. While each system has its own merits, they can be used together to achieve greater process improvement.
