ISO 17025; Rounding Measurements

ISO/IEC 17025:2017 General requirements for the competence of testing and calibration laboratories

Q: At the lab I work for, certified to ISO 17025:2005 General requirements for the competence of testing and calibration laboratories, the documented quality assurance system does not allow the rounding of numbers. For example, the requirement for the weight of an adhesive material is 25 to 35 grams, and the actual weight is 24.6 grams.

The engineering member of the team feels this is acceptable because 25 grams is specified with two significant figures; 24.6 grams, expressed as two significant figures is 25 grams. If the intent was not to round off in the tenths place, the document would read “25.0” and rounding would be in the hundredths.

A: If the requirement (specification) is 25 to 35 grams, the need to specify accurately (24.6 grams) is not as critical and the number can be rounded to 25 grams. We would assume that the nominal desired value would be 30 grams. (Personal opinion: the 25 to 35 gram requirement is a fairly loose tolerance, but I do not know the application).

But, this raises more questions:

How was the weight measured? Was the reported value an average of repeated measurements? Was the measuring instrument capable of reading two or three significant digits? What was the measurement uncertainty of the measurement? Was the measurement uncertainty higher than the 25 to 35 grams requirement?

If the reported measurement was an average of n number of measurements made with a two significant digit measuring scale, the reported averaged is always carried to an extra significant digit. If it was three significant digits, then round to four significant digits.

If the measurement uncertainty was +/- 7 grams, the reported value could fall between 17.6 to 31.6 grams. This scenario would require a better measurement process with smaller measurement uncertainty.

For general number rounding conventions, NIST offers Publication SP811 (appendix B.7 on page 43) which provides a good reference. It can be downloaded as a free PDF.

Dilip A Shah
President, E = mc3 Solutions
Chair, ASQ Measurement Quality Division (2012-2013)
Secretary and Member of the A2LA Board of Directors (2006-2014)
Medina, Ohio

Exploring ACM and BPM

Q: Can someone explain how to use Adaptive Case Management (ACM) and how to incorporate it in a process diagram?

A: First, let’s take a look at Business Process Management (BPM), which approaches the problem of improving an organization’s work from a strongly process centric point of view.  The first thing you think about is the process.  In a certain way, it is the process which defines whether two instances are similar or not.

Data flows into and out of a process. The process represents the goal of a particular sequence of actions, but that goal is not itself an information resource.  The process instance contains process relevant data, as well as application data, but it generally assumes that the data duplicates data that has its source elsewhere. This is the main point about “integration” of the process into other information resources.

 BPM might be visualized as in this diagram:

 Adaptive Case Management (ACM) also tries to improve the performance of an organization, but instead of considering the process to be primary, it is the case information that is primary. This case information is an information resource which will be accessed over the duration of use, and in many situations will become the official record (system of record) for that work.

There can be processes, but the processes are brought to the case, and run in the context of the case, rather than the other way around.

 An ACM system might be envisioned as in this diagram:

Both approaches deal with:

  • Process relevant data
  • Allowing for process requirements
  • Producing historical information that can be analyzed to determine the efficiency of the group involved
  • Availability to multiple people
  • People who are notified of tasks
  • Capturing the results of tasks

At a technical level, these are similar or perhaps even identical. But at a methodological level, i.e., how you approach a given problem, they are at the opposite ends of a spectrum.

In BPM, the process is primary.  Thus, it is predetermined and static, while the data flows through it.  However, with ACM it is the data that is primary.  This tends to persist for a long period of time, but the processes are brought to the data. In many cases with ACM, the processes are not even fully predefined, but must be defined on the fly.

The net result is that BPM and ACM are useful for different kinds of business situations. For example:

  • Highly predictable and highly repeatable business situations are best supported with BPM, e.g., signing up for cell phone service: it happens thousands of times a day, and the process is essentially fixed.
  • Unpredictable and unrepeatable business situations are best handled with ACM, e.g., investigation of a crime requires following up on various clues, going down various paths which are not predictable in advance.   There are various tests and procedures to use, but they will be called upon only when required.

Jack B. ReVelle, Ph.D.
A Consulting Statistician
ReVelle Solutions, LLC
Santa Ana, CA

Guidance on Z1.4 Levels

Chart, graph, sampling, plan, calculation, z1.4

Q: My company is using ANSI/ASQ Z1.4-2008 Sampling Procedures and Tables for Inspection by Attributes, and we need some clarification on the levels and the sampling plans.

We are specifically looking at Acceptable Quality Limits (AQLs) 1.5, 2.5, 4.0, and 6.5 for post manufacturing of apparel, footwear, home products, and jewelry.

Do you have any guidelines to determine when and where to use levels I, II, and III? I understand that level II is the norm and used most of the time. However, we are not clear on levels I and III versus normal, tightened, and reduced.

Are there any recommended guidelines that correlate between levels I, II, III and single sampling plans, normal, tightened, and reduced?

The tables referenced in the standard show single sampling plans for normal, tightened, and reduced, can you confirm that these are for level II (pages 11, 12, 13)?

Do you have any tables showing the levels I and III for normal, tightened, and reduced?

A: Level I is used when you need less discrimination or when you are not as critical on the acceptance criteria. This is usually used for cosmetic defects where you may have color differences, but it is not noticeable in a single unit. Level III is used when you want to be very picky.  This is a more difficult level to get acceptance with, so it needs to be used sparingly or it can cost you a lot of money.

Each level has a normal, tightened and reduced scheme.  I am not sure about what you are asking for with respect to correlation to levels I, II and III and normal, tightened and reduced.  The goal is to simply inspect the minimum amount to get an accept or reject decision. Since inspection costs money, we do not want to do too much. Likewise, we do not want to reject much since that also costs money both in product availability and extra shipping.

Yes, the tables on pages 11, 12 and 13 are for normal, tightened, and reduced, but if you look at the letters for sample size, you will note that in most cases there are different letters for the levels I, II, and III.  Accept and reject numbers are based on the defect level and the sample size. The switching rules tell you when you can switch to either a reduced or tightened level. The tables can handle not just the levels I, II , and III, but also the special levels.

Jim Bossert
SVP Process Design Manger, Process Optimization
Bank of America
Fort Worth, TX

OHSAS 18001 and ISO 9001 Work Environment Requirements

Workplace safety, OHSAS 18001, work environments

Q: We had the opportunity to get the certification for OHSAS 18001:2007 Occupational health and safety management systems — Requirements. While looking at the clause interaction between ISO 9001 Quality management systems–Requirements and OHSAS 18001 given at the end of the standard, I did not find any interaction between the standards for clause 6.4 work environment in ISO 9001.

Am I missing anything or is there any reason for it?

A: I am a U.S. Technical Expert for ISO 9001 and associated  quality management system (QMS) standards and have been involved with QMS standards since 1975.

In my opinion, the answer to your question is that the developers of OHSAS 18001:2007 did not feel that ISO 9001 clause 6.4 related to 18001. This, incidentally, I find puzzling.

The requirement in ISO 9001:2008 Quality management systems–Requirements clause 6.4 reads: The organization shall determine and manage the work environment needed to achieve conformity to product requirements.

In other words, you should make sure that your employees have an adequate work environment for producing your products. They should have adequate room temperature, lighting, and etc.

The 2005 report: Integrated Management Systems (IMS) – Potential Safety Benefits Achievable from Integrated Management of Safety, Health, Environment and Quality (SHE&Q) from Environment Directorate, Organisation For Economic Cooperation And Development, Paris, includes the following which might be of interest to you:

“OHSAS 18001 and National Standards

During drafting of the original BS 8800 a major division of opinion arose as to whether or not independent assessment and certification of an organisation’s OSHMS should be encouraged, as for QMS and EMS.  Some viewed such certificates as valuable, particularly in the context of effective supply chain management, others believed that existing certification processes: added minimal value, required excessive resources and resulted in unused manuals – so new certification processes should be resisted.  It proved impossible to reconcile these views within BS8800, which was structured and published as a non-certifiable standard.

As a result, an international consortium of certification bodies, including the commercial arm of BSI, produced the OHSAS 18001 specification in 1999, followed by implementation guidelines OHSAS 18002 in 2000.  Neither document is an official British Standard, but OHSAS 18001 either is, or is likely to become, a national standard in other countries, notably in Pacific Rim.  A recent survey by BSI identified that over 8000 OSHMS certificates have been issued in 70 countries, to many different standards and guidance, and that some 46% are to OHSAS 18001.

With the revision of BS 8800, from which it is derived, it might be presumed that OHSAS would be updated automatically.  A review is indeed planned, but the decision on when to publish a revision will take into account other factors, including the needs of current new users to have time to ‘bed down’ their internal processes before revising them to meet an improved standard.  When a revision is agreed, it is likely to include some alignment with other high-quality national standards such as AUS/NZ 4801, to aid recognition as a truly global standard.

A new US standard was published in 2005: ANSI/AIHA Z10 – Occupational Health and Safety Systems.  The format includes both a standard and associated guidance, but is not intended as a basis for certification.  It is fully compatible with ISO 9001/14001 and takes account of the other national/global OSHMS documents outlined in this section.”

OHSAS 18001:2007 is not an ISO standard. It appears to be simply an update of OHSAS 18001:2000. Its development was driven by the British Standards Institute which publishes the standard and profits directly from its distribution and sales.

Part of the answer to your question is to evaluate for yourself:

1) Why did you go to the expense to be certified to 18001:2007 and who were the customers that you were satisfying by doing this?

2) What is the expectation of these customers?

From a practical standpoint, consider embracing the concept in ISO 9001 clause 6.4. I would expect that providing your employees adequate conditions for producing products can only improve your product offerings and help to enhance customer satisfaction.

Joe Tsiakals
Voting member of the U.S. TAG to ISO/TC 176 (ASQ)
Voting member of the U.S. TAG to ISO/TC 210 (AAMI)

ASQ re-certification and in-house training requirements

Q: In our corporate audit department, we have a number of individuals that are ASQ certified.  What standards do we need to adhere to in order to provide in-house training that qualifies for ASQ re-certification units?

A: You asked ASQ about standards for granting re-certification units (RUs) from in-house training. There are two main concepts here:

  1. Training must cover some part of the affected certification body of knowledge or be taken for job enhancement.
  2. Every hour of contact time equals 0.1 RU.

Body of Knowledge (BoK). The training topics must cover some part of the certification BoK. This is pretty liberally interpreted. Each certification has a booklet, available for download from the ASQ web site, showing its BoK as an outline of topics. Make sure the training will support one or more of these topics.

Contact time. A one-day course is typically 6-7 contact hours, which would equate to 0.6-0.7 RUs. You cannot count lunch (unless it is a working lunch) or break times – just actual training.

Records. Most people receive a certificate of completion at the end of the training class. It shows name, date, course title, contact hours (or RUs), and person granting the certificate (need not be signed). The employee makes a copy of all these certificates and includes them in the re-certification journal/logbook. Pay particular attention that the date of the class is within the dates of the three-year ASQ certification.

Dennis Arter
ASQ Fellow
The Audit Guy
Columbia Audit Resources
Kennewick, WA

Operational Qualification (OQ) Challenges; Cpk vs. AQL

Q: We’re completing a validation of a plastic extrusion process, which has raised a few questions with me.

This validation exercise encompasses the installation qualification (IQ), operational qualification (OQ), and the performance qualification (PQ). The IQ is self explanatory, but the OQ is challenging. The process is dependent on the batch resin properties which vary enough that the extrusion processing parameters cannot be setup where good parts are always produced. One resin batch can use processing parameters that will not work with the next batch. A justification will be written and included in the documentation package to explain this. Does the inability of defining an operating window void or limit the validation?

My second question has to do with PQ acceptance criteria. The PQ will be three production runs using at least two different material resins (the largest source of variation). While production acceptance will be on an AQL=1.0, C=0 basis, these initial validation lots will be accepted on a process capability index (Cpk) level. While on the surface the acceptance difference may seem benign, it is causing some changes. The tolerance is such that the process routinely passes the Acceptable Quality Limit (AQL) test criteria but fails a Cpk requirement. Is it possible to accept PQ runs as they would be accepted in production?

A related question is the power of a Cpk vs. an AQL sampling plan. A Cpk value can be calculated using the same number of samples on a 100-foot run vs. a 10,000-foot run, while an AQL sampling plan is size dependant. Is there a criterion on sample size or a rule of thumb as to when one plan should be used over another?

A: First, the plastic extrusion process is always a tricky one to qualify simply because each new batch of resin always requires adjustments no matter how controlled the storage conditions are. So yes, you will have to define what adjustments your organization has to make and how big an operating window you need to transition from batch to batch.  If you can demonstrate that it can be resolved within a certain time (say, 15-30 minutes), then it should be ok for validation.  This is assuming that the customer is in agreement with what your company is doing.

Cpk formula, Cpk indexThe second question is a bit more difficult in that the Cpk is assuming that the process is in control and performing at a steady rate.  Cpk is a long term measure and requires the use of control charts to really control the process.  You may be able to work with your customer on help to get validated to the Cpk requirement, but you have to show the plan to get here.  In the past, some customers have been willing to provide an extended period to attain validation. You may want to talk to your customer representative to find out what help they can provide.

The third question gets to the fundamental heart of the situation: the question of using Cpk vs. AQL.  Cpk is a measure of process capability and AQL is a measure of long-term, outgoing quality.  Are they the same?  On some studies I did early on with Cpk and specifications, it was not always clear.  I have not seen any criterion on sample size on when to use Cpk vs. AQL.

Jim Bossert
SVP Process Design Manger, Process Optimization
Bank of America
Fort Worth, TX

Six Sigma Standard

DMAIC process

Q: How are the new ISO 13053-1:2011 Quantitative methods in process improvement – Six Sigma – Part 1: DMAIC methodology, and ISO 13053-2:2011 Quantitative methods in process improvement – Six Sigma – Part 2: Tools and techniques standards to be used?

Is it for certifying Green and Black Belts, or what?  Are there plans for “registering companies” to the standard?  Thanks in advance for your response.

A: The scope of ISO 13053-1:2011 is to “recommend the preferred or best practice for each of the stages of the DMAIC methodology used during the execution of a Six Sigma project. It also recommends how Six Sigma projects should be managed and the roles of personnel involved in such projects. It is applicable to organizations using manufacturing processes as well as service and transactional processes.”

Similarly, the scope of ISO 13053-2:2011 is to “describe the tools and techniques to be used at each phase in the DMAIC approach illustrating them through fact sheets.”

There is no plan at this point to develop documents that have for intent, or scope, to certify Six Sigma Belts or to register companies to the standard.

Michele Boulanger
U.S. TAG to ISO/TC 69 Chair, SC7 Expert

Delta triangle

Q: When revising drawings to include the delta triangle in the title block, does the drawing index sheet also contain the triangle in the title block?

A: The term “delta” refers to a triangle placed on the drawing for reference. The triangle is commonly placed next to a dimension, such as 2.65, 5, or other locations where it applies to a feature or item. This is used to refer the reader to a general note that relates to this item.

So if the delta triangle is used as a reference in your main title block, then I would say yes, add it to the index sheet if it makes the reference more clear.

In addition to drawing a reader’s attention to notes, the delta triangle is also quite often used with print revisions. For example, if a drawing was a revision 2, and then a new revision is generated. It might say something simple like, Rev. 3- 2.235 dimension changed to 2.240. Then a delta triangle with the number 3 in it would be next to the 2.240 dimension referring to the revision.

Bud Salsbury
ASQ Senior Member, CQT, CQI

ISO 9001 Management Representative and Reporting Structure


Q: Please define the preferred method of meeting the requirements of the management representative in regards to clause 5.5.2.b in ISO 9001:2008 Quality management systems–Requirements.

My organization has reorganized, and I find the role of management representative somewhat detached. I work for a military organization that would like this role to be several layers below the base captain vs. the open door policy for the management representative used by previous commands. Should the management representative have direct access to the top?

A: There is no defined or preferred method for addressing the reporting arrangement for the management representative to top management. Your organization defines and deploys the approach that is workable for the management representative to report to top management.

Charlie Cianfrani
Consulting Engineer
Green Lane Quality Management Services
Green Lane, PA
ASQ Fellow; ASQ CQE, CRE, CQA, RABQSA Certified QMS-Auditor (Q3558)
ASQ Quality Press Author

ISO 9001 Clause 7.4.1, Supplier Control

Mr. Pareto Head and Supply Chain comic strip

Q: My interpretation of  ISO 9001:2008 Quality management systems–Requirements regarding supplier control as addressed in clause 7.4.1 Purchasing process is that suppliers who would require evaluation, selection and registry, would be those who supply products (or services) which affect subsequent product realization, or the final product.

Excellent examples for our organization would be vendors providing raw material, tool/dies, surface preparation or calibration services.

I also believe that the “extent of control” exercised by the organization, could, in fact, mean that certain suppliers are not controlled (evaluated, selected and registered), due to their lack of impact on product realization.

Good examples here would be stationery or sanitation supplies.

After conferring with several colleagues, we are all puzzled to see freight companies (UPS, FedEx) included as controlled suppliers and nonconformance reports written for failure to comply with the standard if they are not included on our approved suppliers list.

I understand the standard is written to provide a framework, and not examples, however I find this interpretation to be too broad for the intended purpose.

A: Thank you for contacting ASQ’s Ask the Experts program.  The intent of ISO 9001:2008, clause 7.4.1 is to ensure suppliers are selected based upon their ability to meet the organization’s requirements, which generally include quality and delivery of product or service intended for the customer.

As you mentioned, suppliers of office supplies such as paper, printer toner and etc. are not usually included on an approved suppliers list since they have zero impact on the organization’s ability to meet customer requirements.

However, some registrars may consider trucking firms or delivery services such as UPS and FedEx as suppliers of services that could impact an organization’s  ability to meet requirements, such as on time delivery and the delivery of product in an acceptable condition to the customer.

Most registrars welcome rebuttals from their clients regarding audit findings.  This could be an excellent opportunity for your company state its position to the registrar and to understand their rationale as to why they believe UPS and FedEx must be on the approved suppliers list.

The bottom line is that your registrar determines how its auditors interpret audit criteria such as clause 7.4.1.

If it is decided to add these companies to the approved supplier list, it should be a painless process since your company probably already has an established performance history for them.

I hope this helps!

Bill Aston
ASQ Senior Member
Managing Director of Aston Technical Consulting Services
Kingwood, TX