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Difference between Kaizen Theory and Six Sigma |
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If you have any questions about our Quality Matrix, or wish to make any comments, please feel free to send a message to us at quality@artige.com. |
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| Overview |
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This analysis is just one of many comparisons that are offered as part of the Artige Quality Matrix, which can be seen here in its original form. The definitions that are used in these comparisons are the ones that we at the Artige Company use internally and with our clients, derived from the research that we perform as a matter of due course. These definitions are derived from natural laws of physics and statistics, in order to screen our work from the effects of the business press. The original article where these terms are discussed appears here. In other words, we like to think that this work will withstand the scourges of time and not be categorized as "management du jour". |
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| Kaizen Theory |
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Definition |
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One translation of the term Kaizen from Japanese is "to take apart and put back together in a better way". One will immediate recognize that we have a term that relates to quality, as Kaizen relates directly to improvement. This definition even comes with a recommendation on how to accomplish the improvement. Note that the definition does not have a subject, which means that it can be applied to any matter, such as processes, resources or people. |
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| (Continuous Improvement) |
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For all intents and purposes, Kaizen is most often associated with continuous improvement. This is the improvement methodology where small steps are taken in an attempt to improve an existing process. Feedback is collected, and then these results are analyzed. If the review of the outcome proves successful (based on predetermined metrics), the small step change is accepted. Otherwise the process is rolled back to its previous state. This is not a radical methodology. Rather, many small steps are taken to produce desired process improvements instead of one big overhaul. Kaizen is seen by many business people to be a safe way to implement quality. |
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Thanks to the folks at Toyota, the term Kaizen has been applied in a quality context to refer to a human based approach that requires feedback from the people that are familiar with the process and interact with it. The idea here is that the workers experience and knowledge includes both positive and negative aspects of the operation and would be best to know what changes could potentially work or not. There are both advantages and disadvantages to this line of thought, which is why Kaizen is applicable in certain instances. Obviously, the presence of workers with experience is a requirement, which means high turnover facilities will not be a good candidate. It is also well positioned for manual tasks, especially in the service sector. |
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Another offshoot of Kaizen is the thorough use of the employee suggestion box. The Kaizen effort relies upon employee suggestions and cross-functional teams, where empowered employees are encouraged to speak up. Without human intervention, there can be no process improvement using Kaizen. As such, employees are expected to make suggestions in order to raise the quality of the processes they are responsible for. |
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| Six Sigma |
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Definition |
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Six Sigma has come to mean two things. First, it is a focal point or slogan used as a means to coach a company into improving its performance. For example, one firm's Six Sigma program is "a highly disciplined process that helps us focus on developing and delivering near-perfect products and services". Second, Six Sigma is a designation for a regulated program that a firm might elect to use to establish a quality management system in an effort to improve the quality of products produced or services delivered, and then desires to maintain that improved level of performance. The latter definition is the one referenced most often in the popular business press. |
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| General Systems Theory |
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For both definitions, Six Sigma draws upon the general system theory and relies heavily upon statistics, especially statistical process control (SPC), and requires quantitative parameters that can be measured on an on-going basis if it is deployed as a quality management system. This methodology utilizes traditional process control at its best, making Lord Kelvin proud. Process control is the practice of operating a system, measuring externally available parameters, and modifying the process based upon the measurements. The calculations are not random, but based upon statistics, especially standard deviations. |
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Actually, Six Sigma gets its name from the table of probabilities for the normal (Gaussian) distribution that is used in many statistical calculations. The standard deviation variable is typically symbolized by the small Greek letter sigma. A standard deviation in this context is the amount of the population of samples that are expected to be perfect. The higher the standard deviation, the fewer rejects are expected. The amount becomes exponentially smaller as the number of standard deviations increases, which indicates that it will be more difficult to maintain a process within higher levels of standard deviation. |
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| Sigma = 2 Std Dev |
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Back in the good old days when SPC was common practice, a process was considered to be in control when it ran with +/- three standard deviations, or three sigma. Note that number sums up to six total standard deviations. Today, one is not satisfied unless the process runs within six-sigma deviation, leaving little room for error or defects. To give some numbers to these sigma values, one could consider the number of defects one could expect in the different scenarios. For three sigma, one could expect 2.6 defects per thousand units. For six sigma, the rate would be one half defect per billion units. However, there is an additional factor that needs to be taken into account, that of the drift in the process being measured. SPC takes that into consideration, so the typical defect rate realized with six sigma processes increases to 3.4 defects per million units. Note that these values are typical, and a properly run SPC regime will measure the true defect rates. |
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| DMAIC |
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As you can see from the previous paragraph, it is possible to deploy a Six Sigma program with steadiness and purpose. However, SPC is only one portion of a Six Sigma program. Essentially, Six-Sigma extends the process control concepts to process design and improvement. It requires that one take a system view of the business or manufacturing processes and treat them in a systemic manner. An acronym associated with Six Sigma is DMAIC, which stands for the continuous improvement process of Define, Measure, Analyze, Improve and Control. This is a circular process, where the results of the first pass are used to run the second iteration. |
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The hardest part of Six Sigma is defining the system that describes the business process. It is completely up to the business or process owner to select the best places for splitting an enterprise into monitorable systems. The first two parameters of Define and Measure are the numerically manageable parameters. Metrics and goals need to be defined, seeking out those that can be measured and consistently reported upon, that reflect upon some sort of process output. As the process is operated, process measurements are collected and recorded on a periodic basis. |
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The final three parameters of Analyze, Improve and Control act upon the metrics that were recorded, and are of a more qualitative nature. Here one compares the results against the self-determined boundary conditions and goals. The process is investigated when the boundary conditions are exceeded, and problem solving is engaged in an attempt to determine what went wrong and what could be done to improve the process. The metrics also allow for one to be proactive, and start problem solving based on trends that are observed before the boundary conditions are crossed. Main point is that the DMAIC process is never halted, otherwise complacency will set in. |
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The Six-Sigma methodology requires human intervention, as this process occurs around and about the business processes. The data collection aspect can be automated, but does not have to be. The analysis and improvement aspects cannot be automated at this time. The requirement for human intervention, along with its inefficiencies, brings along indirect issues, such as group dynamics and process ownership. To address these inescapable issues, many Six-Sigma methodologies incorporate personnel practices, summarized through the use of mentoring and granting of titles to the practitioners, based upon colored belts. |
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Note that there is difference of opinion on the effectiveness of hierarchical organizations, and quality organizations typically run flat. On top of that the notion that the practitioners of Six-Sigma are limited by the level of expertise that they possess and are only able to draw upon is curious for a quality organization to pursue. Nonetheless, discipline is strongly promoted, as the tighter the control limits (higher the number in front of sigma), the more tedious the effort to maintain control will be. For the most part, Six-Sigma is an incremental methodology. |
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| The Difference |
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The Differences and / or Similarities |
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At first glance, one would think that Kaizen and Six Sigma have a few things in common, in addition to the fact that they both deal with the topic of quality. They are both methodologies that can be used to implement some sort of regime which could potentially instill or improve quality in a firm's offerings, plus both sanction the use of continuous improvement. However, these two methodologies take advance different approaches in their implementation of continuous improvement, resulting in different outcomes. |
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Kaizen offers a somewhat direct approach to improving an existing system, through the application of continuous improvement, using a human-based approach. Although Kaizen does not provide details to every specific situation, it does offer the optimism that an organization will operate better if process improvements are continuously attempted and applied. One could consider this method a direct attempt at improving the lot of an organization. |
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Six Sigma offers a more direct approach to improving an existing system, through the disciplined application of continuous improvement, using a statistical approach applied using general systems theory. Six Sigma does provide a framework in which to apply the continuous improvement, the DMAIC approach. While not presenting exact details for every specific situation, it does offer a consistent methodology. This makes this approach well suited for large organizations that need a firm structure and documented tactics in order to institute process improvements. One could consider this method a direct attempt at improving the lot of an organization. |
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So on one hand with Kaizen we have a methodology that brings us improvement ideas that are related more towards the people running the processes, and allowing them input into the design and improvement of those processes. There are no firm directives that can be followed, only that many small improvements should always be put into service. On the other hand, Six Sigma brings us a different set of improvement ideas that are related more towards setting up a continuous improvement process that has an SPC component and a process assessment component, which will integrate the results of the SPC testing. This means that Six Sigma includes a manual component, which will require discipline to maintain. Also, Six Sigma may not be simple or trivial to implement. One must realize that any time process redesign is suggested, effort must be exerted, and probably capital funds will need to be spent. Process improvement using Kaizen Theory may be simpler to implement and at a lower cost than Six Sigma, as Kaizen can be rolled out on a more informal basis. |
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Both methodologies should result in changes to the underlying operating processes, and they are both open ended as to what processes could be monitored and improved upon. So the main difference between these methodologies is that Six Sigma has some sort of fixed plan that an organization can follow, while Kaizen relies upon group dynamics to indirectly drive the generation of improvement ideas. |
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| Questions |
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1- Is Kaizen Theory part of Six Sigma? |
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The quick answer to this question is NO! As explained above, Six Sigma is typically represented by DMAIC (Define, Measure, Analyze, Improve and Control). Nowhere in there does the term kaizen appear. There is no requirement that a six-sigma process include kaizen features. On the other hand, a process that is managed under six sigma management techniques can include processes that have kaizen aspects to them. The consideration for six-sigma is, what can be measured and controlled? Kaizen offers a means to accomplishing some of the aims of six-sigma, but does not entirely address the concerns of six-sigma. |
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Keep in mind that a six-sigma process processes is one that will be highly monitored. A process with kaizen aspects may or may not have direct monitoring and heavy oversight. Kaizen was meant for improvement, by encouraging worker feedback, so problems are not kept hidden from the people that can act and improve on the process. Six-sigma seeks to make this happen by consistently alerting on irregularities without depending on the fickleness of human intervention. |
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