Lean Manufacturing and Six Sigma methodologies have emerged over the last two decades as exceptionally effective tools for improving processes of all kinds. Beginning with manufacturing and moving quickly to other industries, they are firmly established as preferred techniques for creating dramatic improvements.
What is the difference between Lean Manufacturing and Six Sigma?
If Lean Manufacturing and Six Sigma both result in process improvements, what exactly is the difference between them? And is that difference enough to cause a business to consider using one instead of the other?
The easiest way to describe the difference between the two is that Lean Manufacturing creates improvements by reducing waste and improving the flow of work and processes. Six Sigma, on the other hand, generates improvements through a structured problem-solving methodology, reduction in variation, and application of data-driven statistical tools. They also differ somewhat in how projects are selected, how resources within the organization are structured, and the length of time that a typical project takes.
The following table shows how Lean Manufacturing and Six Sigma compare.
- Identify and reduce waste
- Improve the overall flow of work and processes
- Projects typically take anywhere from one week to three months to complete
- Most readily applicable to manufacturing processes, but is sometimes adapted for other industries
- Uses Value Stream Mapping as primary tool for identifying and dealing with waste
- Organizational resources can vary widely, usually formed on an ad hoc basis with very little training required
- Reduce variation in results through structured problem-solving methodology
- Data-driven statistical applications and analysis
- Projects typically take anywhere from two months to six months to complete
- Applicable to all business processes across most industries
- Uses DMAIC methodology to reduce variation; specific projects often identified from Value Stream Mapping
- Organizational resources usually consist of individuals or teams who have received specialized and ongoing training on Six Sigma implementation
What are the advantages of using them both together?
When used together in an integrated fashion, Lean Manufacturing and Six Sigma can produce even more dramatic results than if used separately. It is important, though, to balance their differences and match up strengths and weaknesses in order to achieve maximum benefit.
Examples of ways that the two can be used to complement each other:
Getting started – When an organization is first getting started on a process improvement initiative, it can be frustrating if progress is slow. A good way to “jump start” improvements is to start with a Lean project to generate quick, concrete results. This will help boost morale and keep motivation high as longer-term Six Sigma projects progress more slowly.
Simple vs. Complex Problems – Lean tools and techniques are somewhat broader in scope and work very well with simple, easy to solve problems. More complex problems, however, respond best to Six Sigma techniques, as they are better able to delve into the details and analyze complex issues.
Project Identification and Prioritization – Lean and Six Sigma fit together very well when it comes to identifying and prioritizing projects. Using the Lean technique of Value Stream Mapping, an organization can benefit from immediate reduction of waste and identify a steady stream of more complex Six Sigma projects to fee into the pipeline. This makes it easier to set priorities and determine which projects to do in which order.
What types of training are needed for each one?
Six Sigma tools and techniques typically are taught in more formal sequence and with distinct certifications (Green Belt, Black Belt, etc.) awarded at different levels. Training for Lean Manufacturing tools and techniques, on the other hand, is less formalized and does not lead to specific certifications.
Six Sigma is easily applied across many industries, so training content and materials can stay relatively constant from company to company. Lean Manufacturing, on the other hand, requires more specific customization based on the industry to which it will be applied. Materials are not as likely to be transferable so more attention must be paid to ensuring content is correct for the unique needs of each company.
Both methods rely heavily on “hands on” activity to fully train participants. In most cases, project teams will include a range of participants with a range of experience. In this way, those who are newer to the concepts and techniques can learn from those who have applied them before, and the organization ensures a steady supply of qualified practitioners over the long term.
What if We’re Only Doing One – Either Six Sigma or Lean Manufacturing?
If you are currently doing just one or the other, congratulations are in order. Either method – Six Sigma or Lean Manufacturing – is an excellent way to improve processes within and throughout a business. The next step in sophistication is to begin integrating use of both methods in order to take advantage of the synergy that is created when they are applied in concert.
Experienced in Six Sigma – Experienced practitioners of Six Sigma are accustomed to highly structured, data-driven tools. They will need to become familiar and comfortable with the broader approach of Lean Manufacturing as well as the quicker pace of the project process.
Experienced in Lean Manufacturing – Experienced practitioners of Lean Manufacturing will need additional training on the more structured methodology of Six Sigma. They will also need to become comfortable with the data side of Six Sigma, which is a bit more complex to master but once understood makes it possible to evaluate and solve complex problems.
Bottom line – which approach is better?
Practitioners of each method may lay claim to superiority, but increasingly, practitioners are acknowledging and actively promoting the benefits of blending the two approaches. There will always be “true believers” in each camp but it is becoming more and more apparent that the value of combining Six Sigma with Lean Manufacturing is far greater than simply the sum of the two parts.
Integrating Six Sigma with Lean Manufacturing leads to a number of benefits, such as:
- Faster results
- Greater involvement at all levels of the organization
- Deal with simple problems quickly and easily
- Deal with complex problems more thoroughly and completely
- Identification and prioritization of projects
- Flexibility in application
- Appropriate tools for many different situations
Most experts now recommend that organizations combine Six Sigma and Lean Manufacturing to gain maximum benefit. If your organization lacks the experience to do so there are any number of consultants, training companies and specials available to help you get started. In the end, it is highly likely that the time and effort will be well worth it once substantial improvements are realized.