## Six Sigma Statistical Meaning

Question

I need to understand the statement, “Adding a 1.5 sigma shift in the mean results …….”
I’m used to the bell curve and + /- three sigma.
How does the extra +/- three sigma fit in, and what is this about moving the mean?
Does ASQ have a good book that includes this detail in with basic statistics?

The idea of 6-sigma leading to a process with 3.4 parts per million defective is not a totally statistical statement.  Using the normal distribution, we know that a process that is centered on its mean will have 0.135% of the distribution outside 3 standard deviations on each tail.  That same process would have 0.00000010% outside of 6 sigma, which does not lead to the aforementioned 3.4 million parts per million outside.  Dr. Mikal Harry in 1992 published a book (see chapter 6) entitled Six Sigma Producibility Analysis and Process Characterization, written by Mikel J. Harry and J. Ronald Lawson. In it is one of the only tables showing the standard normal distribution table out to a z value of 6.  Here is where he stated that processes can shift by 1.5 sigma leading to only having 4.5 sigma limits and the 3.4 parts per million outside the “6-sigma” limits.  I would suggest you look at ASQ’s Six Sigma Forum Division that will help to better explain the rationale for the shift.

Steven Walfish
Secretary, U.S. TAG to ISO/TC 69
ASQ CQE
Principal Statistician
http://statisticaloutsourcingservices.com

For more on this topic, please visit ASQ’s website.

## ISO 9001 Certification and Moving

Question

My small company is considering ISO certification because some of our customers are asking for it. My concern is that if we continue growing at our current rate, we may be moving in 12-18 months. Is ISO certification site specific – i.e. if we obtain certification and then move, do we need to undergo a whole new certification?

After the certification audit your company will get a certificate for three years, and you will be adhered to a surveillance audit each year during the mentioned duration. There is no problem in moving if your moving did not lead to changes in your processes, activities, services or products which were included in your Quality Management System’s scope during the first certification audit, but it was just moving to another address.

Ibrahim Moussa
Founder and Managing Director, at VOICE OF QUALITY for Training and Consulting Services
ibrahim@voiceofquality-eg.com

For more on this topic, please visit ASQ’s website.

## Question

I was introduced to Quality Management (& ISO 9001:2015) recently. The culture of the organization that I am concerned with has not embraced Quality Management, and it is often the subject of outright and unprofessional antagonism. I seek direction in order to arm myself with greater knowledge or qualifications as well as change attitudes toward Quality Management at all levels within the organization. I thought that ASQ would be a good resource. Since there are so many channels, a plethora of literature, and various certifications and conferences, I am a bit overwhelmed. I need to focus my efforts, and I hope to be able to do so with some direction from a professional who can relate to such growing pains. Thank you.

Denis J. Devos, P.Eng
A Fellow of the American Society for Quality
Devos Associates Inc.
(519) 476-8951
www.DevosAssociates.com

It sounds like this company needs a culture change. This change can happen only at the direction of the company’s leadership.
Here’s some suggestions:

1. Each department head has to establish three (3) measurable goals on how his/her department is improving on the quality of their department’s output/work.  These are to be reported at each executive monthly meeting.  Department manager’s must be held accountable for lack of quality improvements.
1. Every individual’s performance review must include “quality performance.”  This also needs to be measurable (less than last year, improved customer satisfaction from surveys, reduced ‘cost-of-quality’, reduced audit nonconformance observations, etc.)
1. If the company has a bonus program, individuals/departments bonus is tied into quality performance.  ISO observation means 10% or more cut in bonus.
1. Have top executives hold meetings on the need for quality and it’s everyone’s responsibility – not just the QA department.  If employees don’t like it they are welcomed to find employment elsewhere.

Jim

Jim Werner
Voting member to the U.S. TAG to ISO TC 176 Quality Management and Quality Assurance
Medical Device Quality Compliance (MDQC), LLC.
ASQ Senior Member
ASQ CQE, CQA, RABQSA Lead QMS Assessor

Fore more on this topic, please visit ASQ’s website.