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What Is Six Sigma?

Six Sigma – what does it mean?

Six Sigma at many organizations simply means a measure of quality that strives for near perfection. Six Sigma is a disciplined, data-driven approach and methodology for eliminating defects (driving toward six standard deviations between the mean and the nearest specification limit) in any process – from manufacturing to transactional and from product to service.

The statistical representation of Six Sigma describes quantitatively how a process is performing. To achieve Six Sigma, a process must not produce more than 3.4 defects per million opportunities. A Six Sigma defect is defined as anything outside of customer specifications. A Six Sigma opportunity is then the total quantity of chances for a defect. Process sigma can easily be calculated using a Six Sigma calculator.

The fundamental objective of the Six Sigma methodology is the implementation of a measurement-based strategy that focuses on process improvement and variation reduction through the application of Six Sigma improvement projects. This is accomplished through the use of two Six Sigma sub-methodologies: DMAIC and DMADV. The Six Sigma DMAIC process (define, measure, analyze, improve, control) is an improvement system for existing processes falling below specification and looking for incremental improvement. The Six Sigma DMADV process (define, measure, analyze, design, verify) is an improvement system used to develop new processes or products at Six Sigma quality levels. It can also be employed if a current process requires more than just incremental improvement. Both Six Sigma processes are executed by Six Sigma Green Belts and Six Sigma Black Belts, and are overseen by Six Sigma Master Black Belts.

According to the Six Sigma Academy, Black Belts save companies approximately $230,000 per project and can complete four to 6 projects per year. (Given that the average Black Belt salary is $80,000 in the United States, that is a fantastic return on investment.) General Electric, one of the most successful companies implementing Six Sigma, has estimated benefits on the order of $10 billion during the first five years of implementation. GE first began Six Sigma in 1995 after Motorola and Allied Signal blazed the Six Sigma trail. Since then, thousands of companies around the world have discovered the far reaching benefits of Six Sigma.

Many frameworks exist for implementing the Six Sigma methodology. Six Sigma Consultants all over the world have developed proprietary methodologies for implementing Six Sigma quality, based on the similar change management philosophies and applications of tools.

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sixsigmamarketing 01-05-2010, 18:35

Good introduction into the basics of Six Sigma.

Definately worth a read.

muhammad 17-07-2010, 07:12

it is very useful article because six sigma become the way which all the combany take this way to make money
thank you for your effort
best regards

Khushbu 11-10-2010, 03:16

Thank you for giving me the meaning of this word ”SIX SIGMA” cuz i hv faced so many problems for this. Thanks once again

fahad shah 05-05-2013, 01:34

khushbu 6 Sigma . u just knew the meaning but whta is in very rare peoples to understand . i give u 1 suggesion only read and under stand THE GREEN BELT of 6 SIGMA . then you complete about 6 sigma …..

Shariff 21-10-2010, 19:03

It was great to known about six sigma defination from your link..

MUKESH WAGHADE 24-10-2010, 03:44

Six Sigma is very good concept and this knowledge can help company to reduce the tedious task while implementing any project.

Alby 31-10-2010, 04:04

I feel every should know about Six Sigma is very important and this link explains in simply words

Aircav64 17-11-2010, 01:11

In the US it’s call “Six Sigma” in Japan it’s called Kaizen or 5 S. I have worked with kaizen and the 5 S since 1993 and with all due repect, I will use these over Six Sigma. (maybe that’s why I keep getting told I’m over qualified) Look at the last sentence. This isn’t process is not taught/instilled with Six Sigma.

5S is the name of a workplace organization methodology that uses a list of five Japanese words which are seiri, seiton, seiso, seiketsu and shitsuke. Transliterated or translated into English, they all start with the letter “S”. The list describes how items are stored and how the new order is maintained. The decision-making process usually comes from a dialogue about standardization which builds a clear understanding among employees of how work should be done. It also instills ownership of the process in each employee.

Vinod Bhardwaj 15-07-2013, 07:54

Six sigma is a data driven methodology which reduces variation and thus minimising defects. While 5 S and kaizen are basically tools for empowerment by people involvement.

David Mundy 08-02-2011, 02:50

I worked under 6-sigma at AT&T. I found it to be an in-humane system that SCRUTINIZES employees way more than what is reasonable. This system treats humans like MACHINES. It puts a computer in command of the person as judge over every move you make. This is like being MICROSCOPED from 50 different parameters… then the boss starts hammering everyone for better efficiency, or accuracy or percent this percent-that. In a highly technical job it is IMPOSSIBLE to attain all the unreasonable goals they push for. It is a RECIPE for someone to go postal… was my experience. I finally had to quit the $32.00 dollar/hr job and go somewhere else that treats me like a human being… for $10.00 per hour! My family is really suffering now. I lost my retirement plans and I am 55 years old! Computers should not be judges of human productivity. Maybe AT&T implemented it wrong or something… I just cant believe all the people commenting on this page sounding like six-sigma is some kind of wonderful thing!!! what is wrong with you people?

james 15-02-2012, 22:25

spot on!!
you are so right.
i work for TYCO under 6-sigma , and all what you said is so true,…

Kevin 18-02-2012, 02:04

James, thanks for sharing your honest comment. I work for a very large global company where corporate management is always pushing six sigma, and I couldn’t agree with you more!

Chris 25-02-2012, 03:41

Sounds to me like it’s a management issue, not six sigma. It’s entirely possible to implement, and if implemented right, keep the abilities of the employee’s in line. If you focus purely on cost, you get the situation where they nit-pick every thing.

Implemented right you can have both worlds, a better work environment, and a better production throughput and quality.

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Otis Spunkmeyer 27-04-2012, 14:38

Sounds like a great system if you’re a drone cranking out millions of widgets. I’m an Computer Systems R&D Engineer where we make anywhere from one to 10 systems. 6-sigma would be a complete waste of time for what I do. The sad thing is that there is lots of managers out there that everything should be done using 6-sigma including R&D. I interviewed with a few of these nut jobs and come to the conclusion it is a big red flag to stay away because idiots are in charge.

s-sigma is a joke!

Sachin 01-06-2012, 15:47

Right, Hapiness is more important than money.

Brian D 06-09-2012, 15:36

Amen, it’s poorly executed at AT&T , and empowers certain individuals to to basacially drive subordinates to the brink.l Rewarding these certian individuals, for applying a system, that is only ” Black or White” , with no real alternate variables being taken into consideration! This is an extremely poor way to run a company that USED to be Employee and Family friendly.

RT 24-09-2012, 08:46

David Mundy, I went through the Six Sigma training at AT&T. It was a very good training and could be a huge value to AT&T. The problem is the management has know idea what 6 sigma is and are more concerned with the fire drill of the day. With 6 Sigma if the management is not on board and knowledgable of the process, the system is a nightmare. So you have experienced this nightmare first hand.

Andrew 21-03-2013, 01:58

As you mentioned sir, it is not some form of business panacea. Nor is it Esperante. Just something that makes sense, if you know what they mean. ERM.

lyn 05-04-2013, 16:47

I really feel for you. I know first hand how your life can be turned upside down. My job and my husbands were outsourced. I was employed by a major corp for 14yrs and my husband for 22yrs. Two different firms and now we went from 160 a yr to unemployment and no benefits. Scary times! I hope things have turned around and yes when the hell is the gov’t going to start charging tarifs for work going overseas! America isn’t what it was.
My co had six sigma I guess we were all replaced.

Vinod Bhardwaj 15-07-2013, 09:01

Six sigma is an old wine in new bottle. It is interpretation of normal distribution which was found by scheward in forties. Computers are used for statistical analysis.

I Know 05-02-2014, 12:29

I, too, worked for AT&T when Six Sigma was introduced in the company. I worked in a switching office as a senior technician mainly troubleshooting problems with the communications equipment when they arose. I found that trying to implement Six Sigma in my line of work was ludicrous. First, the team that was trying to implement changes had no technical background whatsoever. They would look at an issue as if there was only one resolution when many different factors were involved. Troubleshooting a system as large as what AT&T has cannot be punched into a computer and have a solution spit out that is anywhere close to correct. Secondly, they did a time study on us. Now, time studies have their place. But that place is on repetitive tasks. A time study on repairing electronic issues is a waste of time and money, but AT&T gets what AT&T wants, What they will end up with are employees that only do what they are told and couldn’t care less about the company or the customers. It was sickening to watch and maddening to work under.

CHARLES WEBER 08-02-2011, 15:46


Chris 25-02-2012, 03:39

Deming did return from Japan, after he taught them the six sigma processes. There’s a reason the highest honor for quality in Japan is called the Deming award.

Troy Cole 02-03-2011, 15:26

The standard practice of turning numbers of efficiencies with the way the human brain thinks is all in retraining our thought process and our view of what can be humanly achievable, it can be shown to employees on a chalk board daily and that process alone will increase productivity along with ownership from employees.

Welingkar 07-03-2011, 06:27

David Mundy’s response (08 February 2011 02:50) stemming from his plight is understandable and possibly something that all ‘scientific’ management exponents must take into account when using these techniques.

These tools should not become the means for removing people from the job but used to see how human-machine-process interactions can be smoothened to achieve objectives. Unfortunately it is not just the consultants but even short-sighted managements, who are responsible for this mess.

Jim Baker 07-03-2011, 17:17

I am a general proponent of efficiency in manufacturing cycles and the use of six sigma techniques. However, in many industries I say a push for the use of six sigma when the number of products produced is one or two. What on earth is the six sigma on a sample of one? Using techniques to improve the production of an item is the normal work of engineers of all disciplines. I would prefer that we all work towards that goal without increasing compartmentalization of the work.

Dinesh 23-02-2012, 07:28

Very nicely explained Six Sigma.

amin 13-03-2012, 00:46

I am a general proponent of efficiency in manufacturing cycles and the use of six sigma techniques. However, in many industries I say a push for the use of six sigma when the number of products produced is one or two.

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Andy Mottershead 04-06-2012, 04:42

Just started to Study Six Sigma for my MBA, thanks for all the tips and info on this site…..

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Kevin Clay 06-06-2012, 06:18

Very well written and concise article. I especially like the paragraph about return on investment from a black belt. I am going to point my Belt students towards this page as a quick reference to the definition of Six Sigma. I look forward to reading more articles.

MOHAMMAD IMTIAZ H. B. 01-08-2012, 22:13

Hi all,

Six sigma is good to adopt in a manufacturing company only when each and every body understands the concept including the higher management staffs. Must be willing to collaborate and work as a team towards it.

Definitely there are benefits in doing it.

But must not replace people because of that.


Joji Tom Mundakel 19-09-2012, 08:11

The article sounds good. The six sigma is to industry what probably OODA(Observe Orient Decide Act) loop is to the military. The basic principles remain the same most of the time. Its just the jargon that changes. People nowadays like to be esoteric and throw high sounding jargon. I think the best thing is the KISS principle(another jargon) Keep It Simple and Stupid. We somehow seem to be in a continuous process of making life more complicated for ourselves.
The six sigma can generate more money for the company . But does that serve any purpose to people in the company. And at what cost?

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uma 07-01-2013, 20:22

Six sigma definitely doesn’t survive on the high sounding jargon hype. When we had to keep things simple, shouldn’t we know how to do the same? That is where Six sigma methodology helps.. to keep things simple. Everyone will have their own way of doing things and it will become a challenge at an organization level to manage different approaches at the same time. Six sigma is proven to be an easy to understand, systematic, data driven approach which can be adopted by people at all level in an organization. Will it not become simple to understand and manage when the entire organization speaks of same language? When complex tasks are approached systematically, they become easy to manage and control and Six sigma speaks of the same. Decisions are taken better and quicker when data is there to support and this reduces a lot of effort and waste which can result from gut based decisions and approaches.

Santhosh Kumar S 07-01-2013, 23:44

Helpful for a beginner as well as a veteran.

Ben Ace 21-01-2013, 05:59

An Excellente point to improve production and focus on Management Operation based on the objectives and goals for any company apply it’s rule and it company purpose: the Six Sigma (define, measure, analyze, improve, control). Mr.Ben Ace-MBA. San Juan, Puerto Rico.

Dave on a Rave 21-01-2013, 09:34

Six Sigma is just a tool to be used to help a company produce higher quality products or services at lower costs in order to be competitive. Like any tool, if it is used without regard to the human aspects of the workplace, it can have an overall detremental effect and will not likely be sustainable. I’ve seen it executed well and also poorly. In regards to Mr. Munday’s post above, I would argue that it was not Six Sigma nor was it “computers” that caused the problem, but management that executed a program without fully understanding how to do so while maintaining employee dignity, value and trust. That is indeed unfortunate for all involved.

Glenn Paul Limaco 01-03-2013, 10:52

this is what i needed to learn… i have been reading a lot about this and its a field that is very much interesting that can make your brain think endless possibilities…

Menno 03-03-2013, 10:16

“So my mom can understand it” :-) I love it. Oh, and you delivered too. Excellent and concise description of Lean Six Sigma.

Feroz Inamdar 03-03-2013, 22:15

Good introduction into the basics of Six Sigma

Dave McFarland 08-04-2013, 16:52

probably need a little QC on the Cyger Murrow interview – someone needs to check Rick Murrow’s comments: near the 42 second mark: he says to make the customers more competitive, it is to make the businesses more competitive.

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Michael Cyger 08-04-2013, 20:30

Thanks for pointing it out, Dave, so others aren’t confused. It was merely a slip of the tongue. It’s tough to have a conversation for an hour and not mix up a word every once it a while. I’ve just typed three sentences and I’m sure I did it at least once. :)

Anonymous 16-04-2013, 02:34

It seems some people really like sigmasix. But reading the negative comments on this made me cringe. In the stone age I worked in aerospace info tech. Upon occasion I worked on a quality improvements program. I have never heard of sixsigma. But I know that people are not machines. The description calls it a measure of quality that strives for near perfection.

My first thought was, “Humans cannot achieve near perfection easily. That sounds stressful.” Then I wondered, “near perfection at what? Who is tasked with this near perfecting? Who is measuring and ensuring things are nearly perfect?” Perfection is an interesting concept. Is this perfection on a micro level? Or are there sweeping standards of perfection for all?

Someone was talking about how hard it is to work in Info Tech under this system. I believe it. The workflow in certain types of information technology may not be a constant. Your role may be to produce like mad for a while, then hand off your product to another group. Then you are stuck waiting for some other group to finish their part before you get the project back in your lap again. In other words. It’s not that you work every minute. It’s that you are a specialist who does quality work when it is needed. And sometimes you try to look busy while waiting.

Gemma Cody 22-06-2013, 03:53

Anonymous – what you described there is a perfect example of uneven workflow which is exactly the problem that lean sigma focus s upon to fix. Think of a burger van with a queue of customers – getting longer because I can’t find the napkins, because the buns are out the back and someone’s in my way to get the burgers which are being cooked one at a time to order it doesn’t flow very well – and working this sort of job you quickly figure out what is needed – everything to hand – all primed before the rush – always 2 cooked burgers ahead of each order. However in slower paced – less visibly connected to the customer jobs – it is less obvious but still requires the same sort of organisation to gain efficiency and keep the customer happy. Value stream mapping of the overall process is one if the first lean steps to reveal the hold up points and identify overwork / underwork etc. if you have never heard if six signs – perhaps thus us why you can’t yet see how it would help your industry.

Frazer Rendell 18-04-2013, 21:31

A good insight. It seems like this will be perfect in a manufacturing environment where everything is controllable, such as make a bottle of coke. In a service environment which is full of human interaction it might need something else which encourages positive energy from the individual to achieve the best results.

Gemma Cody 22-06-2013, 03:40

Frazer – I agree it does sit well in a manufacturing environment. However it doesnt work just because it involves processes and machines ! In most environments there is human interaction – and it is the most important focus for a successful implementation of improvements ! I know this because I have just completed a project based on – you guessed it making a bottle of coke ! People there also don’t like to be thought of as machines and simply saying “we pay people a lot of money to not make mistakes” ( I.e be perfect) simply does not work. Success comes through engaging people with proven processes – giving them options – asking their opinions – showing them the proof that one method is less likely to cause errors than another – and speaking to them everyday to see how they are adapting – not just when it goes wrong. Conversely – it works in just the same way in the service environment – step one find a simple process or method which minimises mistakes – step 2 engage with the people to implement the new methodology. There are scientific papers showing human failure rates for different conditions and they show there are some very easy ways of reducing human mistakes by eliminating complex / non -routine processes, removing distractions and providing checklists for example. You are 100 times more likely to make a mistake during a complex non routine task compared to a simple routine task – add pressure into the mix and your cruising for a disaster. The failure rate is even proportional to the font size – and having clear visual management is another great way of getting quick results. Anyway the Crux of the matter is – people following good processes – and that applies in almost any environment !

Theresa M. Mostasisa 05-06-2013, 20:19

This was helpful.

JOSEPH SHIHONGA 24-06-2013, 06:12

This why companies in the west and East are doing great while Kenyan companies still lag behind under traditional management processes.I tried to introduce 6 sigma somewhere but unfortunately my boss was semi illiterate and frustrated this great idea from great minds.6 sigma is the way to go

Gary 07-07-2013, 16:56

It replaces intelligence and decision making with mindless calculation.
Great if you have lots of lowly paid, not so bright people involved.
If you are struggling with overheads though, it requires you to do way more work than you would with a well thought out targeted approach.

No-one would be doing it if the large USA customers weren’t forcing people into it.
They like it for use in developing companies where labour overheads are cheap, and they don’t care if they put manufacturers out of business in other parts of the world.

I’m not saying don’t utilise mistake proof methods, but when its overdone like the car companies want it gets crazy.
ie a dob of grease for lubrication.
Car company will want to apply a tolerance , so it becomes 5 grams ±2. Then the system capability has to be evaluated. Then the measurement system needs to be evaluated. ALL IT NEEDS IS A DOB OF GREASE.

Another Engineer 18-02-2014, 02:12

It seems to me that the whole reason for Six Sigma and other quality programs stems from the fact that business management 1) has no means of accurately gauging employee strengths and employing personnel in areas in which their talents are utilized, and 2) places people in positions for which they are not competent. At my job, what this means is that product engineers (who have never worked in manufacturing) design products that are extremely difficult to build and have insane tolerances using components purchased from China that have poor quality control. On the manufacturing side, there are “Senior Manufacturing Engineers” who do not take the time to perform engineering calculations when “designing” their equipment; the result is equipment that performs poorly. The process engineers spend all of their time firefighting and applying band aids to keep production going and the Six Sigma teams spend most of their time solving problems created by incompetence. Most production problems can be prevented by having competent people design the product, process, and equipment. Unfortunately, most companies promote people based on seniority, not competence or intelligence.

Rajashekhar.Patil 12-07-2013, 22:02

Very good article. We have got lot of inputs from this article. We are also planning to do such methodologies in avoiding cost,defects and mistakes for our company products. Well, this was a nice part in doing so..

Vinod Bhardwaj 13-07-2013, 04:37

After you have exhausted with the improvements done using seven basic tools and have a good maturity of control charts, you should go for six sigma approach. Over 80 percentage of problems can be solved by basic seven tools using PDCA approach.

mrsafetyman 04-09-2013, 06:15

six sigma has flaws. No environmental or safety aspects are involved. It may provde verification but it forgets to Validate after verfiication is complete. There are many flaws and just another system someone decided to name six sigma and make huge bucks. Business like steelmaking always provided a quality product years ago before six sigma even presented itself. Everyone is looking for a buzz word process instead of good old hard work determination and documentaeion within each process. Where is the safety work process, the environmental process> all important in the manufacturing process. What else bothers me is the term manufacturing. So does assembly consider itself a manufacturing process or manufactruing facility? The facility assembles it doesnt manufacture. its part of the process. Always bothered me when companies think they are manufacturing when in fact they are vent for the day.

oshs 04-09-2013, 06:22

no way! someone who thinks like I do. I always believed the same that six sigma is another buzz word that falsly implies quality safety and an environmentally friendly company. OK theres ISO 9000, AS9001 for aerospace, etc. what make another buzz word the better process? No prodcut should have any error and without strict quality, verification and re-verification followed by Validation w/signature, Too many lean buddy buddy workplaces are the problem today. Too lean means too overworked, too many depts to handle, too many people to handle, too many processes to handle.and with that comes fatigue and error. Until companies begin to realize Lean is not the answer, rather true time management is(time studies), than accidents, explosions failures will continue

San 05-10-2013, 06:25

I don’t understand the reasoning behind so many comments that support this Six Sigma.. It has an attractive name – and that’s all about it.. As many pointed out, it is meaningless… Just a label for everything that is common sense.. Use your brain guys. I believe common sense and right brains can replace such inhuman good for nothing concepts like six sigma.. Enough is enough burning time and money for practically no gain.. Get back to real work and throw all these junk out of the window.

San 05-10-2013, 06:27

@Vinod Bhardwaj

Wrong. those tools cannot solve the problem… 80% ? please stop this 80-20 useless philosophies… Probably you are working as a consultant or a so called “quality” manager. Are you not guilty of wasting the company’s time and money in pushing your useless propaganda ?

gokul jeughale 22-11-2013, 20:48


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Kimmy Burgess 10-12-2013, 10:05

An extremely sensible, to the point explanation of the concept of Six Sigma to a layman. This helps to introduce and explain the concept to him and lets him understand what he can expect from Six Sigma. It would help a great deal if these articles could be industry specific other than for manufacturing companies. The common mis conception is that six sigma is applicable only to manufacturing companies.

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Kimmy Burgess 10-12-2013, 10:10

It would help a great deal if these articles could be industry specific other than for manufacturing companies. The common mis conception is that six sigma is applicable only to manufacturing companies.

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Katie Barry 10-12-2013, 10:31

@cashinasnap — We have a section of content segmented by industries here: as well as by operations here: All you have to do is search this website to find examples outside of the manufacturing arena.

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Deepak Panda 16-12-2013, 02:30

The term “Six Sigma” refers to the capability of processes to produce output within specifications with high degree of precision. In particular, processes that operate with six sigma quality produce at defect levels below 3.4 defects per million opportunities (DPMO). Six Sigma ’ inherent goal is to improve all processes to that level of quality or better.

Six Sigma is a set of tools used for making business decisions originally developed by Motorola to systematically improve processes by eliminating defects. A defect is defined as nonconformity of a product or service to its specifications. While the particulars of the methodology were originally formulated by Bill Smith at Motorola in 1986, Six Sigma is heavily inspired by six preceding decades of quality improvement methodologies such as quality control, TQM, and Zero Defects.

Sigma King 30-12-2013, 06:27

really good stuff, I never knew six sigma was so important

Engineer SAMIR IBRAHIM 26-04-2014, 23:43

Thank you for giving me the meaning of this word ”SIX SIGMA” I have faced so many problems for this. Thanks once again I am in a process to explane the use of SIX SIGMA to my coleegs.

Hillary Kivadze 06-06-2014, 01:24

I use six sigma as atool to plan,organize,monitor and implement my projects which are so successful. So 6-sigma is aperfect tool in managerial field.

Frank Leach 02-07-2014, 13:20

Having companies strive for perfection could be the death kneel for new technology innovations brought to the forefront by independent inventors. Working from the premise that inventions from independent inventors fail 99% of the time, then you would advise large companies to bar any new idea suggestions from all independent inventors. Who knows, the next break through technology could from that very source.

Aleem Khalid 05-11-2014, 18:19

My 2c
Six Sigma is nothing but common sense …. but its not so common ….and this is the problem Guys. Aleem


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