Lean vs Six Sigma: Which method fits your needs?

As a former industrial engineer who later became a lean management expert, many businesses I’ve worked with have debated Lean vs Six Sigma. Both are process improvement methodologies, but each has a different approach and emphasis. Lean focuses on eliminating waste, while Six Sigma focuses on reducing variation.

The best option for you depends on the specific pain points you’re trying to solve and your goals. So which is it?

Lean Methodology: Origins and Core Principles

The Lean methodology was originally developed in Japan through the Toyota Production System, and it’s a systematic way to reduce waste and increase efficiency in a manufacturing process. I’ve personally witnessed the transformative power of Lean in various industries.

At its core, Lean operates on the following principles:

• Value: What do customers actually value?
• Value Stream: What are the steps in your process?
• Flow: How can you ensure that products or information moves smoothly through the process?
• Pull: How can you produce only what is necessary, exactly when it’s needed?
• Perfection: How can you ensure that your process is continuously improving?

Lean is all about eliminating any activity that isn’t adding value (“waste”). The eight wastes include overproduction, waiting, unnecessary transportation, overprocessing, excess inventory, unnecessary movement, and defects. The goal is to do more with less for customers.

For example, I once consulted with a car manufacturing plant and helped them implement Lean. As a result, they reduced inventory costs by 30% and increased production output by 25%. The secret was getting everyone from the workers on the assembly line to the executives to look for waste and eliminate it.

Lean isn’t just for manufacturing either. I’ve used the exact same principles in healthcare, software development, and even government organizations, and the results are virtually always the same. Reduce waiting, higher quality, and happier employees.

Just remember that Lean is a journey, not a destination. It requires a cultural shift to continuous improvement. It also requires some patience and persistence, but the payoff is well worth it. If you’re interested in specific Lean tools, learn about how Lean tools can improve your business processes.

Six Sigma Methodology: Origins and Core Principles

Six Sigma originated at Motorola in the 1980s and was later popularized by General Electric. It’s a data-driven methodology for process improvement designed to minimize defects and variability.

At its core, Six Sigma leverages the DMAIC process:

• Define: Define the problem and project goals.
• Measure: Gather data about the current process.
• Analyze: Determine the root cause of the problem.
• Improve: Implement and verify the solution.
• Control: Maintain the improvement.

The objective of Six Sigma is to produce 99.99966% defect-free products or services, which translates to no more than 3.4 defects per million opportunities. It’s a lofty aim, but I’ve seen companies accomplish some incredible results.

For example, I once worked with an electronics manufacturer that was experiencing high defect rates. By applying Six Sigma, we were able to reduce defects by 70% in just six months. The key was using statistical tools to identify the root causes of variation and then eliminate them.

The primary downside of Six Sigma is that it’s very data and statistical analysis driven. As a result, you’ll need to make significant investments in training and tools. However, the upside can be massive, as I’ve seen companies save millions by reducing defects and improving quality.

One of the biggest benefits of Six Sigma is that it provides a structured approach to problem solving. Instead of taking a shot in the dark, you use data to make decisions. This is especially useful in complicated processes where figuring out the cause of the problem isn’t immediately obvious. If you’re looking to understand more, visit this link on decision tree analysis to see how data can aid analysis.

Comparing Lean and Six Sigma: Key Differences

Lean and Six Sigma take different angles to process improvement. Lean seeks to eliminate waste and improve flow. Six Sigma works to minimize variability and defects. Both methodologies can help you make significant improvements, just in different ways.

Lean typically starts with a value stream map to identify waste. Six Sigma starts by defining the problem and collecting data. Lean relies on visual tools, such as kanban boards, to manage projects. Six Sigma uses more statistical analysis to identify and solve problems.

The type of projects you select also differs. Lean projects are often chosen based on obvious waste in a process. Six Sigma projects are selected based on analysis of the data to eliminate variation in key quality characteristics.

Here’s a comparison of the main factors:

• Aspect Lean Six Sigma
• Focus Waste elimination Variability elimination
• Primary objective Improve flow Reduce defects
• Key tools Value stream mapping Statistical analysis, DOE
• Project selection Based on identifying waste Bases the project on data analysis
• Role of data Important Crucial

In my experience, deciding between Lean and Six Sigma comes down to the nature of your problem and what your organization is capable of doing. Some organizations leverage both.

Implementation Challenges and Success Factors

Lean and Six Sigma isn’t a walk in the park. In fact, roughly 60% of companies fail to see the desired improvements when they attempt Lean or Six Sigma projects for the first time. I’ve experienced this pain firsthand and I understand why.

The most common roadblocks to success are:

1. Lack of leadership buy-in
2. Employee resistance to change
3. Inadequate training
4. Inability to sustain improvements
5. Incorrect project selection

It takes more than just the right tools and techniques. You also need the right culture and leadership. For example, a previous employer invested a small fortune in Six Sigma training, yet nothing improved. Why? Senior leadership wasn’t involved and middle managers didn’t execute.

You must:

1. Execute on what senior leadership cares about
2. Have senior leadership buy-in
3. Communicate effectively
4. Provide the necessary resources and training
5. Create events to recognize the early wins

Measuring and sustaining improvements is also key. To do this, set metrics and create a cadence to review progress. And integrate whatever changes you made into the regular operating procedures of the business.

Lastly, remember it’s a change management play. As a result, you’re not just rolling out new tools. You’re asking people to think and do their jobs differently. So be patient, but remain steady.

Lean vs Six Sigma: When to Use Each Approach

The decision of Lean vs. Six Sigma depends on what you’re trying to accomplish. I’ve also seen businesses fail by selecting the wrong solution for their problems.

Lean is the better choice most of the time when:

• You can see waste in your processes
• You want to improve flow and reduce lead time
• You want to involve the people who actually do the work

Six Sigma is the better answer when:

• You know you have quality issues, but you can’t see them
• You want to reduce variability in the things you produce
• You have a very complicated process that you need to really break down

Also, think about your resources. You can get started with Lean faster and cheaper. Six Sigma requires more specialized training and more specialized tools.

For example, one of my clients was struggling with patient flow in a hospital. We used Lean to solve their problem, and in six months, we reduce patient wait times by 40%. Another client was a pharmaceutical company, and we used Six Sigma to reduce variability in their processes. They saved millions of dollars by reducing waste.

The industry you’re in might also push you in one direction. Lean tends to be more popular in manufacturing and healthcare. If you’re in an industry that needs to use a solution with a known brand to solve a quality issue, you might need to use Six Sigma.

Combining Lean and Six Sigma: Lean Six Sigma

Lean Six Sigma combines Lean’s focus on waste reduction with Six Sigma’s focus on reducing variability. It’s a very effective strategy, and I’ve seen it produce some outstanding results.

However, it’s not without its challenges. 60% of Six Sigma projects fail, and 40-60% of Lean projects fail to achieve their desired results. Combining them doesn’t magically make these statistics go away.

Lean Six Sigma follows the DMAIC process, but incorporates Lean tools:

1. Define: What’s the problem and what does the customer need?
2. Measure: Gather data and map the process.
3. Analyze: What are the root causes of waste and variation?
4. Improve: Apply solutions using Lean and Six Sigma tools.
5. Control: How do you sustain improvements?

I’ve found Lean Six Sigma to be particularly effective in industries like healthcare, financial services, and retail, as they need to eliminate waste and improve quality.

One manufacturing company was able to reduce lead times by 50% and defects by 80% using Lean Six Sigma. They used Lean to remove waste from the process and Six Sigma to improve quality.

Keep in mind that Lean Six Sigma requires a significant investment in training and changing the culture. However, if you do it well, it will produce significant improvements in efficiency, quality, and customer satisfaction.

Tools and Techniques: Lean vs Six Sigma

Lean and Six Sigma each have unique tools. Knowing these tools can help you determine the right framework.

Lean tools include:

• Value Stream Mapping: Visualize the process flow.
• 5S: Organize the workplace for efficiency.
• Kanban: Control inventory and workflow.
• Kaizen: Continuous improvement events.

Six Sigma tools include:

• Statistical Process Control (SPC): Control the process.
• Design of Experiments (DOE): Optimize process parameters.
• Failure Mode and Effects Analysis (FMEA): Identify potential failures.
• Root Cause Analysis: Identify the root cause of a problem.

Some tools, like process mapping and root cause analysis, appear in both methodologies. My advice is to learn as many tools as possible so you can choose the best framework for the job at hand.

In my experience, the most powerful improvements occur when you use the right tool for the specific problem. Don’t cram a tool into a process just because it’s part of a framework.

Remember, tools are just that – tools. They only work if you know how to use them and select the right one. The key is really understanding your problem before selecting your framework.

In Closing

I’ve seen the impact of Lean and Six Sigma firsthand in my career, and both are excellent process improvement methodologies. Lean is designed to eliminate waste, and Six Sigma is designed to reduce variation. Each methodology has its own unique benefits and ideal use cases.

Bringing them together under the umbrella of Lean Six Sigma is often the best of both worlds. This combined methodology allows you to maximize the benefits of both Lean and Six Sigma. Select the methodology that’s best suited for the specific problems you’re trying to solve and your goals.

Just remember that execution is rarely straightforward. The key factors that determine your success are the support you receive from company leadership, the organization’s culture, and the resources you dedicate to it. With the right mindset and methodologies, you can make significant improvements in both efficiency and quality.