Green BeltIs there a difference between Six Sigma and Lean Six Sigma?

Is there a difference between Six Sigma and Lean Six Sigma?

Lean and Six Sigma are close cousins in the process improvement world and they have lot of commonalities. Now we will talk about the difference between Six Sigma and Lean Six Sigma.

Six Sigma uses a data centric analytical approach to problem solving and process improvements.  That means, there would be time and effort in data collection and analysis. While this sounds very logical to any problem solving approach, there can be practical challenges.

For example, some times we may need data and analysis to be even prove the obvious. That is lame.

On the other hand, Lean Six Sigma brings in some of the principles of Lean. Lean is largely a pragmatic and prescriptive approach. Which implies that we will look at data and practically validate that problem and move on to prescriptive solutions.

Thus combining Lean with Six Sigma, helps in reducing the time and effort needed to analyze or improve a situation. Lean will bring in a set of solutions that are tried and tested for a situation. For example, if you have high inventory, that Lean would suggest you to implement Kanban.

Lean is appealing because most often it simplifies the situation and that may not be always true with Six Sigma.  However the flip side to Lean is that if the system have been improved several times and reached a certain level of performance and consistency, Lean can bring out any further improvement unless we approach the problem with Six Sigma lens, using extensive data collection and analysis.

Looking at the body of knowledge of Six Sigma and Lean Six Sigma, you will find that Lean Six Sigma courses following tools:

To learn Free Lean Six Sigma Primer Certificate Course
To learn Green Belt Online Certification Course
To learn Black Belt Online Certification Course

Here are my observations based on not just training a few hundred Six Sigma Green Belts across different demographics of geography, industry and age group, but also having mentored them for few months after the training:

Here are the 10 things according to me that Six Sigma Green Belts forget within just 10 -days of attending a training program, implying nearly zero retention:

  1. Project Charter: How to a write a business case that convinces the management? And also differentiate it from Problem Statement.
  2. Fish-Bone: What to do after completing a Fish-Bone diagram? Of course, collect data but on what factors?
  3. Gage R&R: Conduct an live Gage R&R study (at least Discrete data).
  4. Sampling: Choosing a sampling scheme and deciding the sample size for data collection.
  5. Descriptive Statistics: Meaningful and practical interpretation of ‘Standard Deviation’. If there is a process with Standard Deviation of 5 minutes, what does this number mean in real sense?
  6. P-value: What does it mean to the business to accept or reject a hypothesis based on P value?
  7. Variation: Identify the major sources of variation that impact a project metric?
  8. Regression: How to use the regression equation to operate the business efficiently.
  9. Control Chart: Explain to a layman (probably a Manager) what an out-of-control data point means in practical sense.
  10. Sustenance: How to make sure the project exists after a year. I don’t mean the project deck! Many times, it is considered that sustenance is not in our hands, but actually it is a skill that can be acquired and needs to be taught to all Green Belts.
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One of the primary reasons, why Green Belts can’t retain these 10 things, is because most of all this is taught in less than a week with little time for things to settle in, and for the participants to relate. One of the solutions, that works well for me as a coach, is to limit the class size to 2 or 3 and spread the program over 60 days. I actually found best results  during my one-on-one training sessions! Return-on-Investment of such executive development programs are at most important and so the business & career benefits recoups these investments. My note will be incomplete if I don’t mention about few things that Six Sigma Green Belt retain very well after the training, even for several years: · How to do Fish-Bone Diagram? · How to play the Gage R&R game? · Remember and recite the phrase “P is low, Null must go” · How to map the process? · What is Value Add, and Non-Value Add?

FMEA is performed to refine a solution just before its implementation, or at the beginning of a project; to investigate if there is a possibility for any anomalies or risks arising during the process.  In simple words, FMEA is a plan to lessen or eradicate risks associated with the process or proposed solutions. It is not only applicable in a Six Sigma project, but also in any IT project management and general purpose risk analysis/risk management. Any anomaly or element can be considered as risk depending on the severity of its impact, frequency of occurrence of its cause, or the incapability of the control system to detect a cause. A risk rating called Risk Priority Number (RPN) can be used as a yardstick to prioritize and proactively mitigate risks; and to create the required focus within the organization to deal with risks. It is calculated as the product of the severity of the effect, into the occurrence of the root cause, into the detection of root cause.

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While the overall objective is to mitigate risks with high RPN, there can be multiple different strategies to do so. We can use 4 such strategies in the following order. The 4 strategies for FMEA that can help you quickly reduce the overall risk rather than flounder.

Strategy 1 – Reduce the occurrence of cause

In a FMEA, consider all the high RPN items, and select the ones with high Occurrence rating. If the occurrence rating is high, then by reducing the frequency of occurrence of cause, you will reduce the number of times failure occurs. This is the most apt and best strategy to adapt as it directly addresses the core issue. However, situations may warrant you to consider other strategies.

Strategy 2 – Reduce impact of failure mode

In a FMEA, if we don’t have high occurrence ratings, then consider all the high RPN items and select the ones with high Severity rating. These are the ones that will create maximum negative impact on a customer, their business, and thus in fact on your business too. By reducing the impact of the effect, you can show the immediate visible impact to customers. Particularly, if there have been escalations from customers, then this strategy will be best suited.

Strategy 3 – Improve the ability to detect risk

In a FMEA, when above strategies aren’t relevant, consider all the high RPN items, and select the ones with high Detection rating. Improving the detection mechanisms means that we have timely information to prevent the cause, or at least contingency, or mitigation. Conventional risk planning usually focuses on this strategy as first priority.

Strategy 4 – Combination of all three strategies

If all three ratings are high & none of the above can be applied in isolation, then see if they can be combined & applied. By following the above 4 strategies in a FMEA, we can systematically and quickly reduce risk in any process or solution in Six Sigma Project.

All processes need a control or management mechanism to ensure that they meet or exceed customer expectations consistently.  Process parameters that go out of control need to be restored back to their normal values. How fast this has to be done depends on the type of process. For a surgeon, he needs to restore parameters back to normal within seconds. Engineers working in processing plants like paint shops need to react within minutes. However, for some processes, a couple of hours or a couple of days would be good enough.

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A process control or management plan, usually prepared in the control phase of a Six Sigma project, provides insights on a reaction or response plan. A reaction plan or response plan specifies a course of action that is needed to be taken when process control parameters go out of control. And, it includes both immediate and long-term actions to restore a process performance to its desired level. There are 5 different types of reaction plans that can be considered while creating a process control plan:

  1. A plan to continue the process with close monitoring: – A process needs to be closely observed to see where it is going wrong, what is causing the parameters to go out of control, and how often is it occurring; for example: the source of the noise level of a generator or machine. Therefore, at this point, continue to run the process but closely monitor it as well. It is indeed, a very low impact reaction plan, but this is good enough for many processes.
  2. Enforce a manual override: – If a system is running automatically, stop and run it manually in order to exert a little more caution. This not only helps observe which part of the process is failing, it also helps to get a better handling of the process.
  3. Follow special instructions: – The next thing to do, when out of control parameters have been identified, is to follow instructions that are kept in place; for example: in case of a fire, check the instructions to find the exits, etc. Therefore if instructions are followed, then it will help bring the process back on track.
  4. Stop and escalate: – If a process goes wrong, and none of the above actions work, only then we should stop a process and escalate it to the experts or concerned department.
  5. Stop, correct, and resume: – This action can be observed if a process goes wrong and none of the above actions work, and if there is an expert among us who can fix the issue. Then, we can stop the process, correct the process and continue the process; while observing if the process has been restored to its desired level of performance. This reaction plan will have a quick and immediate impact. For some critical processes, this reaction plan is very apt.

The concept of a reaction plan or response plan is not only applicable in control phase, but also for standalone situations. Be sure to follow the 5 steps or types of procedures that need to be observed in the event of a process going out of control.

Six Sigma Certification gives power to employees to bring true business transformation. This in turn facilitates an enterprise to provide better products & services to its customers. Any enterprise that certifies employees (or professionals) needs to have the necessary infrastructure such as: Six Sigma training curriculum, trainers, improvement projects, experts to mentor projects, certification criteria, etc. Immaterial of the belt one wishes to acquire, Six Sigma Certifications can be broadly classified as follows:

First Party Six Sigma Certification

Large Enterprises often create their internal infrastructure to certify employees. This infrastructure should include: six sigma experts, trainers, training curriculum, project selection criteria, project mentoring/coaching model, and certification criteria to certify all deserving employees. This helps establish employees as having a class above the rest, thus improving creativity and productivity of quality goods or services. Some examples include GE, Caterpillar, Bank of America, etc. Six Sigma Certification criteria, body of knowledge, and hence proficiency levels vary between different enterprises. The value of such a first party certification is often tied to brand value of enterprises. Hence certificates from fortune 100 enterprises do carry a good deal of recognition in the market.

Second Party Six Sigma Certification

Companies that do not have the infrastructure to train their employees, or lack the expertise, will engage an agency to assess and certify employees. Companies leverage the agency’s infrastructure and credibility to issue co-branded certifications. However, co-branded Six Sigma certifications often come under the scanner, as agencies might be obliged to certify employees purely out of business compulsions.

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Third Party Certification

Here employees get Six Sigma certification from an agency all by themselves. An employee will realize the potential of such a certification in today’s competitive job market, and drive him/herself to complete their certification. The advantage with this type of certification is that it is a purely neutral certificate. Of course, the brand of agency matters and the employee will need to satisfy all criteria to get certified. Due to lack of a universal certification body, many agencies may have diluted certification standards. This makes it easy to receive a certification, but with little real value attached to it. If you are looking for a six sigma certification, then, check your options. Consider the following:

A good trade-off will be to receive training from a reputed organization in fulfilling the above guidelines, and then take the Six Sigma Certification from an industry recognized body like ASQ. This way you get the best of both!

Floundering teams – A source of failure for six sigma projects… many can’t believe, but it’s true. Aptly ASQ has included this topic in their SSGB BoK. The meaning of Floundering is to struggle or stagger clumsily as if confused. Floundering often results from a lack of clearly established goals, unclear tasks, discomfort with other team members, or due to overwhelming emotions.

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Six Sigma projects often fail due to floundered teams.  Project sponsors and Six Sigma Green Belts have to address such issues quickly, but they themselves are victims. This amplifies the problem and makes it one of the biggest failure modes for Six Sigma projects. If you aren’t convinced, consider the following:


We hope this resource Floundering teams – A source of failure for Six Sigma Projects will help manage your Six Sigma Green Belt projects effectively.

First time, I ever heard the term Six Sigma, I was puzzled, lost and obviously amazed. Here was a term that I couldn’t make out a bit. I felt exactly the same when I first heard H2O from my primary school science teacher. By the way, what is Sigma in Six Sigma? That’s the next question that I wanted someone to answer. The Six Sigma Black Belt who introduced this term to me in a training, gave a very complicated answer, which confused me further. In those days, Google didn’t exist, so I flipped many pages of our company’s Six Sigma manual, and then couple of statistics books, but I finally reconciled. Sigma is the Greek alphabet (in small letters), which is used to represent ‘Standard Deviation’. Sigma (standard deviation) has been in existence since the days of Gauss, who found out the bell shaped curve. But it has become very popular after Motorola coined the term Six Sigma. Now, this methodology has evolved into Lean Six Sigma. Without complicating things for you, Standard Deviation is a measure of variation that exists in any process. The term variation itself is very simple to understand. For example, if your morning newspapers arrive between a time window of 6 to 9 am, while your friend’s newspapers arrive between 7 to 7:30 am, then your ‘newspaper delivery process’ has high variation compared to your friend’s. So, let’s learn standard deviation in layman’s language, so that we can understand what is sigma in Six Sigma in practical sense. Standard Deviation is the average distance of all the data points from their average. Let’s consider the time when your newspaper gets delivered, for a week : Mon – 6:30 am, Tue – 7am, Wed – 6:45 am, Thur – 8 am, Fri – 6 am, Sat –  8:30 am, Sun – 9 am. For this data, the average time when newspaper gets delivered is 7:23 am. So some days delivery is before this time and some days after. Next, you compute the difference between each day’s delivery time and average time for all 7 days, i.e, for Monday : (6:30 am – 7:23 am ) = – 0:53 minutes, and likewise for all values.

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Now, we need to calculate the average of all these differences. But the differences you compute will have both minus and plus values. If we add them as such, they will nullify. That wouldn’t work. So, we use the following approach.

Finally, the value you get after finding the square root, is the Standard Deviation. For this example, standard deviation or Sigma turns out to be nearly 1 hour (precisely 62 mins). This means that your newspaper boy is on an average one hour ahead or behind than his usual delivery time of 7:23 am. Coming back to our original question, what is Sigma in Six Sigma? So Sigma is a measure of variation in any process. Higher the sigma, higher is the variation, which is undesirable. So, one could compare two similar processes for their Sigma values and find out which one is better. In this case, your friend’s newspaper delivery boy is better than your delivery boy! This will give you a simple idea of What is Sigma in Six Sigma, but this is only understanding half the story. You still need to understand What is Six in Six Sigma in our next article. Six Sigma Certification Course Team

This is the second article in the series that will help understand What is Six in Six Sigma? If you haven’t already read our article ‘What is Sigma in Six Sigma‘, we would like to recommend that you first do so. For now, let’s look into what is Six in Six Sigma. Let’s get started by understanding Customer Requirement and Actual Performance. We are going to use the example of newspaper delivery everyday to your house. As a customer, you want newspapers to be delivered between 7:00 and 7:30 am (say within a half hour window). However, in reality, the paper gets delivered only between 6:00 to 9:00 am (a 3 hour window). So, in this case, the customer requirement or allowable variation is ’30 mins’ while the Actual Performance or Actual Variation is 3 hours. On the contrary, your friend isn’t so particular about his newspaper delivery. He is in fact fine if they are delivered between 6:00 to 9:00 am (a 3 hour window). But in reality, his papers get delivered between 7:00 to 7:30 am (a half hour window). How would you characterize these two situations?

Now, let’s answer the question ‘What is Six in Six Sigma?’ Six refers to the Sigma Capability of any process. In this case, the newspaper delivery process. When it’s Six, it means that the Standard Deviation or Sigma is so small that 6 Standard Deviations or 6 Sigmas can be fitted on either side of the bell-shaped curve. Based on the principle of bell-shaped curve (normal curve), 6 Sigma equals only 3.4 defects per million opportunities. For the newspaper example, it means that if there are 1 million days of newspaper delivery, only on 3.4 days (i.e. 3 or 4 days) of the delivery will be beyond your requirement. So, it is very obvious that your newspaper delivery isn’t at the Six Sigma level, but your friend’s delivery could be. It depends on the value of Standard Deviation. We covered the computation of standard deviation in ‘What is Sigma in Six Sigma’.

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Let’s say for your friend’s process, only 5 standard deviations or sigmas can be fitted on either side of the bell-shaped curve, then, his sigma capability is at 5 or his newspaper delivery process is at 5 Sigma. To sum up, if you want a particular process to be at Six Sigma, then you will have to manage the following: Understand what the customer requirement is? If there is a window within which the customer wants her delivery or quality, then that becomes your customer requirement.

Six Sigma has evolved as a management discipline for improving processes, and providing customer delight. Some organizations like GE had adopted Six Sigma as their management philosophy. So, Why Six Sigma? Why not follow other approaches like TQM, SCM, COPC, ISO, etc. Let’s understand why many organizations choose Six Sigma over other approaches; and how they benefited. There are 3 key salient features of Six Sigma that are noteworthy:

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Customer Centricity

While the emphasis on building business processes to meet customer requirements was first proposed by Joseph Juran & Edward Deming (fathers of modern Quality movement);  it was taken seriously only with the advent of Six Sigma. Gathering the Voice of Customer and translating these requirements into product features, aka Quality Function Deployment (QFD), were loosely used in TQM. Whereas, in Six Sigma Voice of Customers (VOC) is the starting point. Operational measures and performance measures (KPIs) are built based on VOC. These measures are called as CTQ (Critical To Quality). Customers’ needs constantly change. Such changing needs mean that processes also need to adapt and evolve. Six Sigma enables achieving this adaptation. While creating a new product or service line; the entire system is built to meet customer requirements. Such an approach is called as Design for Six Sigma (DFSS).

Process Orientation

Six Sigma builds strong process orientation within the organization. In Six Sigma, virtually every department, activity, or task is perceived as a process in itself or process step. What does that mean? It means a lot! Every process produces few outputs, and in turn; requires few inputs. Outputs are consumed by Customers (internal or external); and inputs are provided by Suppliers. Such visualization is called as SIPOC in Six Sigma. This helps organizations to move away from the mind-set of fixing people when things don’t work; to fixing processes. In order to improve the outputs of any process or department, its process steps and inputs needs to be improved, and sometimes suppliers need to be educated. People are never penalized in Six Sigma! Traditionally many industries & functions are regarded as ‘people’ driven. For instance, industries such as Hospitality, Entertainment & most service lines and functions such as HR, Marketing, Sales, Admin. Six Sigma organizations treat these as just another process. As a result, the dependency on individuals is also reduced. Organizational silos are challenged and processes are simplified. Driving strong process orientation across the organization has resulted in unbelievable tangible and intangible benefits to customers and organizations. GE is a pioneer in driving process orientation in its Financial Service businesses.

Fact Based Decision Making

Once organizations establish process orientation; access to data and factual information will increase. This presents the next big opportunity for organizations. Across levels, organizations are dependent on their managers to take right decisions. Most often, these decisions are punctuated by decision maker’s bias and personal intuition. Wrong decisions are costly and usually borne by the organization. Six Sigma’s bouquet of tools enables data or fact based decision making. This means the overall management is much more efficient and accurate. DMAIC, an acronym for Define, Measure, Analyze, Improve and Control, is a method used for solving problems. There are over 50 qualitative and quantitative tools which are part of DMAIC. These tools can be applied in several stand-alone situations too. These tools enable data or fact based decision making. At a personal level, an individual practicing Six Sigma over a period time is more efficient and effective than her peers. This has direct impact on career and growth prospects. Thus Six Sigma is a powerful approach which is not only beneficial to organizations; but also to individuals. If you are interested in Six Sigma Certification Courses, visit our products page. Click here

Have you ever thought about this before – Will Six Sigma help me become a better leader? Isn’t leadership a soft skill unlike Six Sigma? Six Sigma is more about playing with numbers, statistics, Minitab!!! Ask leaders of organizations that follow Six Sigma as a management philosophy, and they will disagree.

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A true practitioner of Six Sigma is a great leader. All basic principles of Six Sigma help to be a better leader:
  • Customer Centricity
  • Data or Fact Based Decision Making
  • Strong Process Orientation
  • Structured way to improve, design and sustain processes

Let’s consider 4 important dimensions of leadership that most world class organizations strive to instil in their associates.

  • Ability to grow the business
  • Capability to lead the team to deliver
  • Drive culture of execution
  • Conviction to sustain the momentum & optimism

Let us consider one at a time, and understand how Six Sigma can help focus on these 4 aspects.

Ability to grow the business

 Capability to lead the team to deliver

 Drive Culture of Execution

 Conviction to sustain the momentum & optimism

So a good leader will not miss a single opportunity to apply the above principles of Six Sigma in their business to deliver results consistently. That is why at many world class organizations, Six Sigma is in the fabric of who they are. So, beyond doubt, Six Sigma help me become a better leader!

Six Sigma & Project Management are two high trending topics of interest among professionals and organizations today. While Six Sigma is a management approach, project management principles instill the rigor of execution. Whatever is the nature of your business, innovation is critical today. In order to survive competition and be the customers’ choice, you need to come up with really new products and services.
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All it means is that your change management ability is a direct measure of your success. In other words, timely launch of new products/services in desired quality and price are going to determine your success; apart from the cultural change aspect. So whether you want it or not, good project management skills are essential in today’s business to survive and win. Without digressing on other pre-requisites of good project management, let’s focus on one of most important but rarely focused area. There are several project management techniques and tools available, such as: CPM, PERT, and Critical Chain. Immaterial of the base on which these models are structured, out of my experience, everything finally boils down to predicting the time duration for a task and delivery as predicted. In small organizations (less than 10 employees), it is more of coordination, multi-tasking, and communication that will determine if a task can be completed as predicted. But with organizations involving a few hundreds of employees, it is all about how resources and efforts are synchronized. There may be lack of knowledge of what is to be done next, on who owns which piece, how & when to escalate, and lack of clarity on authority & decision making. Additionally, unlike big organizations, smaller companies will have to manage with inexperienced and understaffed scenarios. So to make life easy for everyone; if processes associated with project management such as supply chain management processes, finance processes, clearly defined inter-department service levels and authorities, etc., are established well; it will help the organization deliver projects in time. Isn’t this what ‘Process Orientation’ is all about! Strong Process Orientation: one of the key foundations of Six Sigma is responsible for success in most project based industries. Mathematically also it makes sense to focus on process orientation. For instance, consider the PERT model in which the PERT Time (Task duration) is a function of Optimistic Time (OT), Most Likely Time (MLT), and Pessimistic Time (PT). When OT and PT are wide apart, it means that it is not possible to predict the task duration accurately. In other words, the process on which the task is dependent has high variation. Such a process leads to higher PERT Time. When all the tasks of a project have widely spread OTs and PTs, the overall project duration itself will be high and unpredictable.

Lean Six Sigma Project – A beginner’s guide is a series that explains how to run Lean Six Sigma projects in detail. The biggest benefit of combining Lean and Six Sigma is to deliver more value to customers and business. In order for a Six Sigma Green Belt to be successful with a project, they must know what’s to be done, and how to accomplish them! This guide is a step-by-step procedure to execute the 5 phases of a Lean Six Sigma project.

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Lean Six Sigma improvement projects follow 5 phase DMAIC approach. A six sigma project is not an academic exercise, but its primary objective is to impact customers, business, and employees positively. Thus stakeholder buy-in and sponsorship are very important factors for its success. Every project should have at least one project sponsor (One sponsor is just fine, two is OK, but greater than that is undesirable). The project sponsor is usually the process owner or a senior management executive who is accountable for the overall project and its success. They take the lead in identifying the project & its objectives, and in team formation. The team composition should be cross-functional. The sponsor also has to decide whether this Six Sigma project should be led by a Black Belt or Green Belt. Once identified, the respective Six Sigma Belt plays the lead role in the project. It is their responsibility to complete the project on time, and deliver desired results. Now, for the remaining part of this beginner’s guide, let’s assume that it is a Lean Six Sigma Green Belt Project. The duration of a typical project should be between 3 to 4 months. The overall project plan for all Six Sigma improvement projects are mapped to Define, Measure, Analyze, Improve, and Control. There are defined deliverables for each of these phases which have to be accomplished before progressing further. At the end of each phase, a formal tollgate is used to stage a gate review by the sponsors. Various Six Sigma concepts and tools can be applied to progress and accomplish desired phase-wise outcomes. In order to make sure the project meets the timeline, and set-out objectives; the Green belt and team members are to meet regularly. In addition to this, Six Sigma Green Belts are mentored by Black Belts or Master Black Belts. In a nutshell, following are the broad outlines for each of the DMAIC phases of Lean Six Sigma Project:

Next, as a part of this beginner’s guide, let’s understand how to accomplish the deliverable of the Define phase here

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