Ask the Standards Experts

Six Sigma Case Studies

Suppliers, supplier management

Q: I would like to browse through detailed Six Sigma Case Studies. I do not mind making a payment for detailed case studies in the fields of manufacturing, services and software.
Kindly direct me to the requisite links please.

A: Thank you for contacting ASQ. I received your request for case studies on Six Sigma in the fields of manufacturing, services, and software.

“Six Sigma is an organization-wide approach used to achieve breakthrough improvements tied to significant bottom-line results. Unlike previous TQM approaches, Six Sigma specifies exactly how the organization’s managers s hould set up and lead the effort. Key features are the use of data and statistical analysis, highly trained project leaders known as Black Belts and Green Belts, project selection based on estimated bottom-line results, and the dramatic goal of reducing errors to about three per million opportunities” (taken from The Quality Toolbox, 2nd ed. by Nancy R. Tague)

ASQ has around 300 Six Sigma case studies available online.

A host of additional Six Sigma content is also available.

Scope of ISO 19011:2011

ISO documentation practices, requirements

Q: During a quick review of a recently revised standard, ISO 19011:2011– Guidelines for auditing management systems, we noticed that it is shorter than ANSI/ISO/ASQ 19011S:2008.

Also, we are wondering why there are no references to auditing the requirements in ANSI/ISO/ASQ Q9001-2008 Quality management systems.

Could someone please address our concerns?

A: With the expansion in scope of ISO 19011:2011 to cover all management system audits, the intent of the ISO 19011 standard is to provide guidance that is applicable to every management system discipline – not just quality management system audits.

One of the problems with the more general scope of ISO 19011:2011 is that it less helpful for addressing specific issues – such as internal audits of an organization’s quality monitoring and measuring processes. This is why the ASC Z1-auditing subcommittee has initiated the process of developing supplemental guidance documents for internal audits and supply chain audits. If there are specific issues or questions that you are interested in, you can ask that it be included in this supplemental guidance document (email standards@asq.org).

As to the difference in length – with the U.S. adoption of ISO 19011:2011, the 2008 U.S. Supplement was made obsolete. What the Z1-auditing subcommittee is planning to do is to capture whatever guidance in that document is still important in the new supplemental guidance documents being drafted.

Thea Dunmire, JD, CIH, CSP
Chair, ASC Z1-Audit Subcommittee
ENLAR Compliance Services, Inc.
http://www.enlar.com/
Largo, FL

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

ISO 9001:2008 and Reasons to Obtain Third-Party Certification

Reviewing confidential files, training records, human resources files

Q: I have a question regarding an excerpt about ISO 9001:2008 — Quality management systems –Requirements, from the ISO webpage, which is below:

“…Although certification is not a requirement of the standard, the quality management systems of about one million organizations have been audited and certified by independent certification bodies (also known in some countries as registration bodies)…”

Our ISO 9001 quality management system (QMS) has been registered through third-party audits since 1994. But according to this statement, we should be able to represent ourselves as an ISO 9001 organization by simply meeting the requirements of the standard. These requirements, of course, don’t require third-party certification.

Is this the case? If not, isn’t the statement on the website misleading, in as much as certification is an implicit requirement of the standard?

A: I am a U.S. Technical Expert for ISO 9001 and associated QMS standards, have been involved with QMS standards since 1975 and am a published Quality Press author.

You are correct when you state, “we should be able to represent ourselves as an ISO 9001 organization by simply meeting the requirements of the standard. These requirements, of course, don’t require third party certification.” Many organizations use ISO 9001 as the basis for their quality management system without engaging in third-party audits. If you want to claim certification, I guess you could claim that you are “self-certified,” but I am not sure this would mean anything to anybody.

There are a variety of reasons for incurring the cost associated with obtaining an ISO 9001 certification:

Internal use: Many do this based on a perception of market advantage and use the certificates in advertisements promoting their goods and services. Some organizations use third party audits and certification to verify for their own management the adequacy of their quality management system.

Supplier qualification: The historical use for a quality management system standard is as a basis for qualifying the quality management system of suppliers. Development of quality management system standards dates to the 1950s. One of the early standards of this type was MIL-Q-9858A used by the Department of Defense for use in qualifying some of their suppliers.

Today, ISO 9001 is widely used as a qualification requirement for suppliers in many different product and service sectors. The automotive, aerospace, telecommunications and other industries have sector specific versions of ISO 9001 that are used with suppliers. These all require third-party certification.

Regulatory requirement: The European Union, FDA, Japan, Australia, Canada and many other countries use ISO 9001 as the quality management system for meeting certain regulatory requirements. Some regulatory bodies require third-party certification, others conduct their own audits (second-party audits) to verify compliance.

Bottom line: you should determine for yourself if you have a need for certification to ISO 9001 and act accordingly.

Joseph Tsiakals
Voting member of the U.S. TAG to ISO/TC 176 on Quality Management and Quality Assurance (ASQ)
Voting member of the U.S. TAG to ISO/TC 210 Quality Management and Corresponding General Aspects for Medical Devices (AAMI)

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

Sampling Plan for Pharmaceuticals

Pharmaceutical sampling

Q: We are a U.S. dietary supplements manufacturer operating under c-GMP conditions set by the U.S. Food & Drug Administration (FDA).

As such, we perform analyses of incoming raw materials (finished product ingredients), intermediate products (during manufacturing), and finished products. Analyses include identity testing (incoming raw materials), and other types of analysis (e.g. microbiological, heavy metals, some quantitative assays on specific compounds). These tests would be the attributes we wish to assess.

Basically, we are refining our sampling procedures and need to ascertain an acceptable number of samples to be taken for the various testing purposes outlined above.

The World Health Organization’s (WHO) Technical Report Series No. 929, Annex 4, “WHO Guidelines for sampling of pharmaceutical products and related materials” references ANSI/ISO/ASQ 2859-1:1999 Sampling procedures for inspection of attributes – Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection in reference to the selection of a statistically-valid number of samples for testing purposes.

I note from your website that there are a number of other sampling standards available. I am seeking some guidance as to the most appropriate standard(s) for our particular purposes.

Any assistance you can offer would be much appreciated.

A: Though many of the sampling plans are similar, many standards organizations have published different interpretations of sampling schemes. Since WHO recommends using ISO 2859-1 as the guidance document, I suggest selecting that plan.

There are similar documents that could be used as an alternative, if necessary:

1. ANSI/ASQ Z1.4-2003 (R2018): Sampling Procedures and tables for inspection by attributes

2. BS 6001-1:1999/ISO 2859-1:1999+A1:2011 Sampling procedures for inspection by attributes. Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection

3. MIL-STD-105E – Sampling Procedures and Tables for Inspection by Attributes*

4. JIS Z9015-0-1999 Sampling procedures for inspection by attributes — Part 0 Introduction to the JIS Z 9015 attribute sampling system

A few points to consider:

Usually for FDA-regulated products, a c=0 sampling plan is appropriate. See H1331 Zero Acceptance Number Sampling Plans, Fifth Edition, by Nicholas L. Squeglia
Based on risk, an Acceptable Quality Level (AQL) should be selected
Your sample size is usually set to be proportional to lot size. If you are doing testing on bulk raw materials, the sample size will be set based on the variability of the lot as well as the variability of the method.

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

Note:

*Military standard, cancelled and superceded by MIL-STD-1916, “DoD Preferred Methods for Acceptance of Product”, or ANSI/ASQ Z1.4:2008, according to Notice of Cancellation

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Sampling Employee Tasks

Employees, Training, Working, Learning, Duties, Tasks

Question

We are collecting data on what tasks our employees in various departments do each day. We hope to eventually get a representation of what each employee does all year long. Randomly, throughout the day, employees record the tasks they are doing. We are not sure how to calculate an appropriate sample size and we are not sure how many data points to collect.

Answer

I wish there was a simple answer. We need to consider:

If it makes a difference on how long an employee has been performing a job?
Are the departments are equivalent in terms of what they are doing?
What is the difference that you want to detect?

The simple rule is that the smaller the difference, then the larger the sample size. By smaller, it is less than 1 standard deviation from the data that has been detected.

Random records are O.K., but really, shouldn’t you want a record for everyone for at least a week? That would give you an idea of what is done across the board and, then, if you are trying to readjust the workloads, you have some basis for it based on the logs. My concern with the current method is that you may have a lot of extra paperwork to account for everyone for a certain time.

Additional information provided by the questioner:

The goal of this project is to establish a baseline of activities that occur in the department and to answer the question “What does the department do all day?”

The amount of time an employee has been performing a job does not make a difference. The tasks performed in each department are considered equivalent. We are not accounting for the amount of time it takes to complete a task — we are more interested in how frequently that task is required/requested.

The results will be used to identify enhancement opportunities to our database and identifying improvements to the current (and more frequent) processes. The team will use a system (form in Metastorm) to capture activities throughout the day. Frequency is approximately 5 entries an hour at random times of the hour.

I have worked with the department’s manager to capture content for the following fields using the form:

Department (network management or dealer relation)
Task (tier 1)
Why (tier 2 – dependent on selection of task)
Lessee/client name
Application
Country
Source of request (department)

We are looking for a reasonable approach to calculate the sample size required for a 90 – 95% confidence level. The frequency of hourly entries and length of period to capture the data can be adjusted to accommodate the resulting sample size.

Answer

The additional information helps. Since you have no previous data and you are getting 5 samples an hour from each employee, (assuming a 7 hour workday, taking out lunch and two breaks), that will give you approximately 35 samples a day. Assuming a five-day week, that gives you approximately 175 data points per employee. This should give you enough information to get an estimate of what is done for a week.

Now, you will probably want to extend this out another three weeks so that you have an idea of what happens over a month. If you can assume that the data collected is representative of all months, then you should be O.K. If you feel that some months are different, then you may want to look at taking another sample during the months where you anticipate different volumes from the one you have. You can use the sample size calculation for discrete data using the information that you have already collected and not look at all employees, but target your average performers.

Jim Bossert
SVP Process Design Manger, Process Optimization
Bank of America
ASQ Fellow, CQE, CQA, CMQ/OE, CSSBB, CMBB
Fort Worth, TX

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

QMS Documentation Management

About ASQ's Ask the Standards Expert program and blog

Q: I was wondering if ASQ has any good information on managing QMS documentation. My company is working right now on finding a solution for a better way to manage QMS documentation. We have previewed some QMS document management software but think we can do all of the programming in house with Microsoft SharePoint. If you have any suggestions I would love to hear them.

A: Thank you for contacting ASQ. According to The Quality Improvement Glossary by Donald L. Siebels, a quality management system is “a formalized system that documents the structure, responsibilities, and procedures required to achieve effective customer satisfaction levels”.

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

Integrating ISO 22000, ISO 14001

Food safety testing, lab, standards

Q: In a food manufacturing company, with certifications to ISO 22000:2005 Food safety management systems — Requirements for any organization in the food chain as well as ISO 14001-2004: Environmental management systems – Requirements with guidance for use, the certification to ISO 22000 allows the company to operate with exemption from the Food Act. The exemption from Food Act determines that the organization has a permit to use its physical premises to indulge in industrial activity involving consumable food products.

Now, this permit is issued with certain conditions — e.g., regular updates to the issuing authority regarding changes to to the food safety plan. We view this requirement as a legal requirement.

My question is, would we use the legal register developed as part of ISO 14000 as the tool to manage the compliance to the above legal requirements? Doubt arises because the legal requirement addresses a condition imposed by the food safety system, but at the same time, if it is not complied with we could lose our license to operate (which I could interpret as an environmental aspect…license to exist).

Could someone kindly advise what they would consider to be a logical option?

Response from Susan Briggs:

A: I am not a food safety expert, so I cannot give an opinion on whether or not using a register/process established for environmental regulations can be used for tracking food safety regulatory requirements. But from the ISO 14001 perspective, and my professional opinion, the answer is “of course!.”

The intent of management system standards — certainly all of the ones I have worked with– is to integrate the processes that are required by a standard (whether it be ISO 14001, ISO 22000, etc.) into the company’s business management process (i.e., a single process that is used to track all of the company’s legal obligations…environment, safety, finance, food safety, etc.), not to create stove piped processes (i.e., separate processes/systems for tracking depending on the nature of the regulation).

Susan Briggs
Director of Environment, Health and Safety, Textron Systems
Wilmington, MA
Chair, U.S. TAG to ISO/TC 207 on Environmental Management Systems

Response from John Surak:

A: I am not sure what is meant by the term “exemption from the Food Act.” ISO 22000 requires that the organization meet all of the legal requirements of the country in which the site is located. In addition, if the organization is exporting food, they must meet all of the legal requirements of the target company. ISO 22000 was developed to be compatible with the other ISO management system standards. Therefore, it is fully permissible to develop an integrated management system as long as the management system meets the requirements of each standard and regulatory requirements. I personally support the development of an integrated management system. Sue conveyed this thought very well in her response.

Just one additional note, if the organization’s customers expect that the organization has a food safety management system that meets the requirements of Global Food Safety Initiative (GFSI), then the organization should seek registration to FSSC 22000 rather than ISO 22000. FSSC 22000 is a food safety audit scheme that utilizes ISO 22000 and ISO 22002-1.

John G. Surak, PhD
Surak and Associates
Clemson, SC
A member of Stratecon International Consultants
http://www.stratecon-intl.com/jsurak.html

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

Applicability of TS 16949 to Non-Manufacturing Organizations

Q: My conpany is certified to ISO 9001:2008 Quality management systems–Requirements. We provide integrated circuit chip design and outsource the manufacturing of the IC chips to our approved subcontractors. Recently, we won a contract to design and supply chips to one of our customers who, in turn, supplies to the automotive industry (the first automotive customer for my company).

One of the key deliverables of this project is to get ourselves certified to TS16949:2009 Quality management systems — Particular requirements for the application of ISO 9001:2008 for automotive production and relevant service part organizations in the next 6 to 9 months.

We would like to know:

1. Is TS 16949 applicable to a company, like mine, that does no manufacturing?

2. In general, what does it take to be at least compliant to the TS16949 requirements?

3. Since TS 16949 is based on ISO 9001 with additional requirements, does that mean that once a company is certified to TS16949 it is not necessary to recertify to ISO 9001?

A: Thank you for your questions.

The answer to your first question is that a company like yours is not eligible to become registered to TS 16949 because it is not a manufacturer. Clause 1.1 General of TS 16949 states this very clear:

“This Technical Specification is applicable to sites of the organization where customer-specified parts, for production and/or service, are manufactured.”

Furthermore, clause 3.1.11 from Terms and Definitions defines a “site” as:

“Location at which value-added manufacturing processes occur.”

Your second question is about how to attain TS16949 compliance. Simply, you would need to purchase a copy of TS16949 and ensure that your ISO 9001 quality management system meets all of the TS16949 requirements. The biggest difference between ISO 9001 and TS16949 are the requirements associated with advanced product quality planning (APQP) and production part approval process (PPAP).

The answer to your third question is yes, registration to TS 16949 includes full compliance with all the requirements in ISO 9001. A separate registration is not necessary.

If you have further questions, please don’t hesitate to ask.

Denis J. Devos, P.Eng
A Fellow of the American Society for Quality
Devos Associates Inc.
London Ontario
www.DevosAssociates.com

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

ISO 2859-3 Skip-lot Sampling 5.1.1, 5.2.1

Suppliers, supplier management

Q: Our quality team is trying to improve inspection efficiency and enhance supplier management by employing ISO 2859-3:2005 Sampling procedures for inspection by attributes — Part 3: Skip-lot sampling procedures.

Here are two questions on product qualification related to clause 5.2.1 Generic requirements for product qualification.

1. The standard requires that:

b) The product shall not have any critical classes of nonconforming items or nonconformities.

First, my understanding is that the risk level with any potential failure or nonconforming of the product should be low to customer — is this correct? Second, if a candidate product carries some critical features (dimension of mechanical product), but also carries a number of low risk features, can we apply the skip lot concept only to the non-critical features? And continue to perform lot-by-lot inspection with critical features? We are concerned the definition of “product” in the standard is a generic term and could be interpreted as feature of a physical product.

2. The standard requires that:

c) The specified AQL(s) shall be at least 0,025 %.

Does this mean the AQL value should be less than or greater than 0.025%? I assume “greater.” In our company, the most often used is AQL 1.0 and AQL 2.5, which I think meets the requirement.

We would greatly appreciate your help.

A: My name is Dean Neubauer and I am the U.S. Lead Delegate to Subcommittee 5 on Acceptance Sampling and Quality Press author. I hope I can help you.

Let’s start with question 1.

The general idea of skip-lot sampling is to reduce the number of times incoming lots inspected due to exceptional quality on behalf of the supplier. ISO 2859-3 states this in the beginning as:

The purpose of these procedures is to provide a way of reducing the inspection effort on products of high quality submitted by a supplier who has a satisfactory quality assurance system and effective quality controls.

The reduction in inspection effort is achieved by determining at random, with a specified probability, whether a lot presented for inspection will be accepted without inspection.

A skip-lot sampling plan is also known as a cumulative results plan. In general, such plans require certain assumptions to be met regarding the nature of the inspection process:

The lot should be one of a continuing series of lots
We expect these lots to be of the same quality
The consumer should not expect that any lot is any worse than any of the immediately preceding lots
The consumer must have confidence in the supplier not to pass a substandard lot even though other lots are of acceptable quality

Under these conditions, we can use the record of previous inspections as a means of reducing the amount of inspection on any given lot. ISO 2859-3 states the above in 5.1.1 Requirements for supplier qualification:

The requirements for supplier qualification are as follows.

a) The supplier shall have implemented and maintained a documented system for controlling product quality and design changes. It is assumed that the system includes inspection by the supplier of each lot produced and the recording of inspection results.

b) The supplier shall have instituted a system that is capable of detecting and correcting shifts in quality levels and monitoring process changes that may adversely affect quality. The supplier’s personnel responsible for the application of the system shall demonstrate a clear understanding of the applicable standards, systems and procedures to be followed.

c) The supplier shall not have experienced any change that might adversely affect quality.

The underlying assumption here is that the supplier quality is exceptional (low nonconforming level). The skip-lot plan is applied to each characteristic, or feature, separately. If several characteristics are present, then try to test for at least one of them. In your situation, if you have critical characteristics you should not be doing skip-lot inspection due to the risk of ignoring (skipping) a potentially dangerous lot. On the other hand, you can use a skip-lot plans for non-critical (major and minor) nonconformities and they will have different AQL levels associated with them. Your listing of AQLs of 1.0% and 2.5% are typical for major and minor nonconformities. Critical defects will typically have an AQL less than 1.0%, such as 0.25% to 0.65% (0% is preferred but theoretically unattainable as you would have to do a perfect 100% inspection, i.e., no inspection error).

The subclause referenced in question 2 states that the AQL level must be greater than or equal to 0.025%. Your levels of 1.0% and 2.5% can be used.

Dean Neubauer

U.S. Lead delegate for Subcommittee 5 on Acceptance Sampling on ISO Technical Committee 69 on Applications of Statistical Methods.

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

Variation in Continuous and Discrete Measurements

Force majeure

Q: I would appreciate some advice on how I can fairly assess process variation for metrics derived from “discrete” variables over time.

For example, I am looking at “unit iron/unit air” rates for a foundry cupola melt furnace in which the “unit air” rate is derived from the “continuous” air blast, while the unit iron rate is derived from input weights made at “discrete” points in time every 3 to 5 minutes.

The coefficient of variation (CV), for the air rate is exceedingly small (good) due to its “continuous’ nature” but the CV for iron rate is quite large because of its “discrete nature,” even when I use moving averages for extended periods of time. Hence, that seemingly large variation for iron rate then carries over when computing the unit iron/unit air rate.

I think the discrete nature of some process variables results in unfairly high assessments of process variation, so I would appreciate some advice on any statistical methods that would more fairly assess process variation for metrics derived from discrete variables.

A: I’m not sure I fully understand the problem, But I do have a few assumptions and possibly a reasonable answer for you. As you know, when making a measurement, using a discrete scale (red, blue, green; on/off, or similar), the item being measured is placed into one of the “discrete” buckets. For continuous measurements, we use some theoretically infinite scale to place the units location on that scale. For this latter type of measurement, we are often limited by the accuracy of the equipment to the level of precision the measurement can be accomplished.

In the question, you mention measurements of air from the “continuous” air blast. The air may be moving without interruption (continuously), yet the measurement is probably recorded periodically unless you are using a continuous chart recorder. Even so, matching up the reading with the unit iron readings every 3 to 5 minutes, does create individual readings for the air value. The unit iron reading is a “weights” based reading (not sure what is meant by derived, yet let’s assume the measurement is a weight scale of some sort.) Weight, like mass or length, is an infinite scale measurement, limited by the ability of the specific measurement system to differentiate between sufficiently small units.

I think you see where I’m heading with this line of thought. The variability with the unit iron reading may simply reflect the ability of the measurement process. I do not think either air rate or unit iron (weight based) is a discrete measurement, per se. Improve the ability to measure the unit iron and that may reduce some measurement error and subsequent variation. Or, it may confirm that the unit iron is variable to an unacceptable amount.

Another assumption I could make is that the unit iron is measured for the batch that then has unit air rates regularly measured. The issue here may just be the time scales involved. Not being familiar with the particular process involved, I’ll assume some manner of metal forming, where a batch of metal is created then formed over time where the unit air is important. And, furthermore, assume the batch of metal takes an hour for the processing. That means we would have about a dozen or so readings of unit air for the one reading of unit iron.

If you recall, the standard deviation formula is divided by square root of n (number of samples). In this case, there is about a 10 to 1 difference in n (10 for unit air to one for unit iron). Over many batches of metal, the ratio of readings remains at or about 10 to 1, thus impacting the relative stability of the two coefficient of variations. Get more readings for unit iron or reduce the unit air readings, and it may just even out. Or, again, you may discover the unit iron readings and underlying process is just more variable.

From the information provided, I think this provides two areas to conduct further exploration. Good luck.

Fred Schenkelberg
Voting member of U.S. TAG to ISO/TC 56
Voting member of U.S. TAG to ISO/TC 69
Reliability Engineering and Management Consultant
FMS Reliability
http://www.fmsreliability.com

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