Six Sigma has been around for more than a decade. Lean for nearly as long. Each is unique and yet shares a number of common attributes with the other. Why do they garner the attention they do? How are they different or similar to previous business revolutions from Deming to Reengineering to Total Quality Management? Aren’t they just applicable to manufacturing? And why would I want to spend the time to learn them and use them in my own situation?
Both Lean and Six Sigma are related to prior attempts such as the Deming Method and Reengineering to offer continuous improvement methodologies for businesses. In fact, many of the Six Sigma statistical methods were introduced into manufacturing first by Deming. As with other programs both have seen great success, when applied correctly, and abysmal failure, when improperly utilized. Each has strengths and weaknesses; however, when applied together they create a strong base for productivity in any organization.
I personally look at Lean as a set toolbox given to organizations to apply quickly. These tools are simpler in nature when compared to the statistical intensity and rigor of Six Sigma. The simplicity of the tools belies their impact. One of the first tools in Lean is 5S. Yet, rarely have I seen a situation where companies apply the 5S (Sort, Sift or Simplify, Sweep, Standardize, and Sustain) and then proceed onto the next Lean tool. In most cases multiple applications of 5S are utilized to reach optimal performance before more complicated tools are applied.
For example, I was working with a tool called a spaghetti chart on a process that required simplification. A coworker leaned over my shoulder and asked quizzically, “What’s that?” I explained that it was a picture with all the physical locations in a process and that I was tracing where the employee had to physically go to complete a task. The steps can then be optimized so that less travel is required. I thought nothing of it until 3 weeks later when I happened by his desk. What did I find? You guessed it a spaghetti chart that he had created for a process he had to deal with all the time. He had already started to campaign for changes using the information. There was no formal program to initiate his quest, he just realized that he could apply the concept to visually demonstrate his frustration in a way that other could readily see and they would then be more open to discussing possible changes.
The multiple applications and simplicity of Lean tools allow for easy cross training of the tools within an organization so that very quickly they are being applied throughout an organization and not just in a targeted area. Six Sigma on the other hand lends itself much more to the difficult questions where we may not know the optimal answer or where the simpler Lean tools are not providing a ready solution on their own.
I tend to view Six Sigma as more akin to the scientific method. You need to define the problem before you go off and gather the statistical data that you will utilize. As in a scientific lab, if the approach is not carefully setup a project leader may end up spending hours or even weeks collecting data only to discover it doesn’t provide the appropriate information. However, when properly controlled the Six Sigma toolbox, similar to the scientific method, provides information that was not previously known. Outputs often provide not only the relationships between known variables, but also information on hidden variables or how variables combine to produce overall impacts to processes and products.
For example in one project that I was a part of the organization was having issues with final product testing. The issue appeared random in the products it affected and at which test station it occurred. After discussing with both design engineering and manufacturing engineering, it was decided to run a battery of tests on each of the test stations using the same products. Two major issues were able to be uncovered using the statistical tools; interestingly, neither of the issues were related to the product – which is where all the prior attention had been paid. Both of the issues were related to the test stations themselves. The first was unique to a particular test station. It was determined that this station was not being maintained properly and repairs were initiated to eliminate those issues. However, these were only a small subset of the issues. The overwhelming majority of the problems were related to improper siting of the stations. The stations did not meet their installation specifications because they were situated to close to one another. This created interference between the stations and impacted the product test results.
Without the more detailed structure of the Six Sigma approach the efforts would have continued to be placed on the product or the assembly process rather than the test stations. The rigor and statistics of the Six Sigma tools do require more training in order to properly utilize them, but in many cases the impact of the tools can be significantly greater due to the power the data can have in arriving at solutions. In addition the outputs are often detailed mathematical relationships between processes and products that provide a ready made set of levers that can be utilized by the organization to optimize an upcoming situations and not just existing ones.
This brings me to what I consider the most important issue in regards to Lean Six Sigma. Whether used separately or together they are still just a set of tools in the hands of personnel trained to use them. Similar to the tools of a production worker, the presentations of a sales team, or the spreadsheets of a finance manager; they cannot provide a revolution in any organization on their own. As I stated before Six Sigma is based on a lot of the work that Deming started many years prior. The tools themselves have in many cases been around. Deming in fact took the tools to Japan after World War II and introduced them to Japanese industry. Toyota took them onboard modified them, improved them for their own use, and eventually produced the Toyota Production System (TPS). Lean pulls many of its lessons from TPS. Each of the systems Lean, Six Sigma, Deming, Reengineering, Total Quality Management, and more that haven’t been mentioned, provide a process to achieve improvements. However, none of these systems can provide the culture in which to utilize them to their best benefit. How to make those changes will have to wait for another time as I’ve reached my allotted space for this column.