The simple answer is that if anyone is making decisions about product or process 'acceptability' (does it meet a specification), then the equipment used should be calibrated or at least verified as operating correctly.

It really doesn't matter (to your management) what the ISO standard says, since most management have never read it or know why it exists, however, they might see the benefit of either having problems of processing or production/productivity because the operators didn't get the correct data they needed to control the thing.

If they are concerned about the cost of calibration or the disruption of removing the equipment to perform the calibration, there are many ways to over come that resistance.

Do you have anyone in the organization who is experienced in running an effective calibration management system? If not, it could be useful to find one.

The simple answer is that if anyone is making decisions about product or process 'acceptability' (does it meet a specification), then the equipment used should be calibrated or at least verified as operating correctly.

"Calibrated" and "verified as operating correctly" are the same thing.

It really doesn't matter (to your management) what the ISO standard says, since most management have never read it or know why it exists, however, they might see the benefit of either having problems of processing or production/productivity because the operators didn't get the correct data they needed to control the thing.

While I'm not sure if I agree that most management types are ignorant of the reasons for the standard's existence, they are most likely to be motivated by fiscal concerns rather than honoring the standard, per se. They become more likely to want to honor the standard when it's demonstrated that not honoring it will have economic consequences, in other words. For this reason it's good to be able to show management the consequences of forgoing an efficacious calibration system. This becomes somewhat more difficult to accomplish if there are no examples at hand, but you can still use hypothetical situations to demonstrate the need.

"Calibrated" and "verified as operating correctly" are the same thing.Not at all, Jim. Calibration is not the same thing as verification. Calibration is normally performed, through a chain of unbroken comparisons, to a standard, SI unit.

Verification is usually performed where traceability to such a universal standard isn't possible, say to a known 'gold' standard. Also, verification can be simple check to see if the device is functioning correctly, without the need to control the factors affecting calibration (see ISO/IEC 17025:2005, for example)

Indeed, the ISO 9001 requirement distinguishes between calibration and verification.........

Not at all, Jim. Calibration is not the same thing as verification. calibration is normally performed, through a chain of unbroken comparisons, to a standard, SI unit.

Verification is usually performed where tracability to such a universal standard isn't possible, say to a known 'gold' standard. Also, verification can be simple check to see if the device is functioning correctly, without the need to control the factors affecting calibration (see ISO/IEC 17025:2005, for example)

Indeed, the ISO 9001 requirement distinguishes between calibration and verification.........

"Calibration" is the act of comparing a measuring device to a standard. ISO 9001 requires traceability of standards. Calibration may or may not involve adjustment. ISO 9001-2000, 7.6 says, in part, that measuring equipment shall...
...be calibrated or verified at specified intervals, or prior to use, against measurement standards traceable to international or national measurement standards...There is no explanation given for the difference between "calibrated" and "verified" in this context. In either case, the requirement for traceable standards applies, (unless no traceable standard exists) so there is no substantive difference between the two.

"Calibration" is the act of comparing a measuring device to a standard. ISO 9001 requires traceability of standards. Calibration may or may not involve adjustment. ISO 9001-2000, 7.6 says, in part, that measuring equipment shall...
There is no explanation given for the difference between "calibrated" and "verified" in this context. In either case, the requirement for traceable standards applies, (unless no traceable standard exists) so there is no substantive difference between the two.

I agree with Jim,

Calibration and verification require comparison with traceable standards.

Stijloor.

Allow me to elaborate on calibration and verification. ISO 9001:2000 was written with a much broader context in mind then ISO 9001:1994. Many tend to think in a traditional way regarding measuring instruments (hardware) and required calibration. In the context of ISO 9001:2000, the term "verification" can be applied to lab equipment, PLC's, computers and devices other than those typically seen in a traditional manufacturing environment.

We're all creatures of habit and we need to think outside the typical "hard-core" manufacturing context.

Just my :2cents:

Stijloor.

"Calibration" is the act of comparing a measuring device to a standard. ISO 9001 requires traceability of standards. Calibration may or may not involve adjustment. ISO 9001-2000, 7.6 says, in part, that measuring equipment shall...
There is no explanation given for the difference between "calibrated" and "verified" in this context. In either case, the requirement for traceable standards applies, (unless no traceable standard exists) so there is no substantive difference between the two.

You are right Jim.When you calibrate,you are simply verifying,that the instrument/tool in question is within the designated permissible limits.Hence the real difference is in the nomenclature,but not in the implied meaning.

Umang :agree1:

So help me out, here, then.

If there's no difference, why not just say either 'calibrated' or 'verified'? Why say 'calibrated or verified' if they are the same thing? Did the committee who wrote the requirement get paid by the word?

So help me out, here, then.

If there's no difference, why not just say either 'calibrated' or 'verified'? Why say 'calibrated or verified' if they are the same thing? Did the committee who wrote the requirement get paid by the word?

Andy,

There are industries, organizations, where the word "calibration" may not as common as "verification." Remember the term "Inspection and test?" Now it's called: "Monitoring and measurement of product." Same thing. But again, "inspection and test" may not be as familiar in certain organizations.
I am not a linguist, but that's how I look at it.

Semantics? :frust:

Stijloor.

Then TC 176 should have put the definition in ISO 9000 with the others. They saw fit to do that will all kinds of simple words - like competence - so based on your description, if these organizations don't know verification from calibration, it should be spelled out for them.

Inspection and testing isn't a good analogy. Measurement and monitoring were chosen since the scope of 'product' was widened, from the origins of ISO 9001/2/3 - the BS 5750 requirements, and military requirement before that, in which product was hardware.

Incidentally, you can verify a (working) pressure gauge, for example, by putting a master pressure gauge along side it, to check the line pressure as a comparison........it's only reading at a single pressure, perhaps, but it might show that the working gauge is 'off'.

The calibration of the same pressure (working) gauge would be performed on (for example) a deadweight tester, up and down the full scale, at increments against known weights, traceable to a NIST std.

How is the verification, by comparison, the same thing as calibrating over a range, on a deadweight tester?

BTW, Jim - I didn't mention any adjustment, since I'm well aware that calibration is simply the determination of the reading to the standard!:rolleyes:

How is the verification, by comparison, the same thing as calibrating over a range, on a deadweight tester?

It's obviously not the same thing; one method is more comprehensive than the other, but both are calibration, and both are verification. In case I've missed it, please tell us where the two words are defined in the standard.

BTW, Jim - I didn't mention any adjustment, since I'm well aware that calibration is simply the determination of the reading to the standard!:rolleyes:

I didn't mean to suggest that you were unaware; sometimes we include information with a wider audience in mind.:D

It's obviously not the same thing; one method is more comprehensive than the other, but both are calibration, and both are verification. In case I've missed it, please tell us where the two words are defined in the standard.

So, Jim; why not just use one word........if it's the same thing? BTW - you know it's not defined in there, you're just pulling my leg;)

I know my language is full of wonderful words which mean the same thing, but c'mon, now - you don't seriously expect me to believe that TC 176 had the exactly identical meaning in mind, when they wrote those words into the requirement, do you??:rolleyes:

Webster's Encyclopedic Unabridged Dictionary of the English Language:

Calibrate
1. to determine, check, or rectify the graduation of (any instrument giving quantitative measurements).
2. to divide or mark with gradations, graduations, or other indexes of degree, quantity, etc., as on a thermometer, measuring cup, or the like.
3. to determine the correct range for (an artillery gun, mortar, etc.) by observing where the fired projectile hits.

Verify
1. to prove the truth of, as by evidence or testimony; confirm; substantiate.
2. to ascertain the truth or correctness of, as by examination, research, or comparison.
3. to act as ultimate proof or evidence of; serve to confirm.

Don't know if this helps....:frust:

Stijloor.

So, Jim; why not just use one word........if it's the same thing? BTW - you know it's not defined in there, you're just pulling my leg;)

I know my language is full of wonderful words which mean the same thing, but c'mon, now - you don't seriously expect me to believe that TC 176 had the exactly identical meaning in mind, when they wrote those words into the requirement, do you??:rolleyes:

I'm not pulling anyone's anything. It says "calibrated or verified," but then doesn't say anything about the distinction. If it's a significant distinction, don't you think they would have defined their terms?

Look: if I have a calibration system that meets ISO requirements, then production and inspection measuring equipment will be included in it, and I''l rationally define intervals, the qualifications of people who do calibrations, and use traceable standards. All of it will be duly documented. But, if I compare a measurement instrument to a standard between defined intervals, and find that it's OK, I'm calibrating it, whether or not the calibration is noted in the system. By calibrating it, I am performing an act of verification. I honestly have no idea how this can be a matter of contention.

Allow me to elaborate on calibration and verification. ISO 9001:2000 was written with a much broader context in mind then ISO 9001:1994. Many tend to think in a traditional way regarding measuring instruments (hardware) and required calibration. In the context of ISO 9001:2000, the term "verification" can be applied to lab equipment, PLC's, computers and devices other than those typically seen in a traditional manufacturing environment.


Verifying PLC's, computers? Based on this and Jim's assertion that calibration and verification are the same thing makes this statement very misleading. Computers are not verified or calibrated. The 'software' used to log or manipulate the measurement data has to be 'validated'. Again, check out what ISO/IEC 17025 says in 5.4.7.

Verifying PLC's, computers? Based on this and Jim's assertion that calibration and verification are the same thing makes this statement very misleading. Computers are not verified or calibrated. The 'software' used to log or manipulate the measurement data has to be 'validated'. Again, check out what ISO/IEC 17025 says in 5.4.7.

That's wat I meant (sorry). Devices + software that drive advanced metrology and testing quipment. Now we have a third word in this conversation:
1. Calibration
2. Verification
3. Validation

Gentlemen, it's Saturday evening...I'm bailing and rest my case..

Y'all have a great weekend.

Stijloor.

Wow, what an interesting discussion going on :)

Its 7 am in China; just got up and logged on elsmar :):D

I have an interesting link which gives this difference in a simple manner -

http://www.agilent.com/metrology/cal_or_verify.shtml

Calibration, Verification or Conformance ?

When discussing calibration requirements with a potential supplier it's obviously important to understand what's being offered. Other articles in this section should help you to establish your requirements and distinguish the differences between available services. But one of the variations has, sometimes, even confused calibration laboratories and quality auditor. It's a matter of the difference between calibration, verification and even conformance.

Similar to the often confused specification terms accuracy and precision, a myth became "established wisdom" that calibration and verification are differentiated on the basis of quality or integrity.

Popular opinion being that verification is a quick-check of performance perhaps made without any real traceability, whereas calibration provides genuine assurance that the product really meets its specification. In fact, the US national standard ANSI/NCSL-Z540 defines "verification" as being calibration and evaluation of conformity against a specification. This definition originated with the now obsolete ISO/IEC Guide 25 but neither its replacement (ISO/IEC 17025) or the International Vocabulary of Measurement (VIM) currently have it or any alternative. The only relevant international standard that includes terminology covering the process of both calibrating and evaluating a measuring instrument's performance against established criteria is ISO10012 which uses the rather cumbersome term "metrological confirmation".

Calibration is simply the process of comparing the unknown with a reference standard and reporting the results. For example:
Applied= 1.30V, Indicated= 1.26V (or Error= -0.04V)
Calibration may include adjustment to correct any deviation from the value of the standard.

Verification, as it relates to calibration, is the comparison of the results against a specification, usually the manufacturer's published performance figures for the product. (e.g. Error= -0.04V, Spec= ±0.03V, "FAIL"). Some cal labs include a spec status statement on their Certificate of Calibration. (i.e. the item did/did not comply with a particular spec).

Where no judgment is made about compliance, or correction has not been made to minimize error, it has been suggested that Certificate of Measurement would be a more descriptive title to aid recognition of the service actually performed. Some suppliers also use Certificate of Verification where no measurements are involved in the performance testing (such as for certain datacomm/protocol analyzers), rather than Certificate of Functional Test as this latter term is often perceived as simply being brief, informal checks as might be performed following a repair (often termed "operational verification").

Verification can also relate to a similar evaluation process carried out by the equipment user/owner where the calibration data are compared to allowances made in the user's uncertainty budget (e.g. for drift/stability between cals) or other criteria such as a regulation or standard peculiar to the user's own test application.

Verification is not intermediate self-checking between calibrations. Such checks are better termed confidence checks, which may also be part of a Statistical Process Control regime. The results of confidence checks may be used to redefine when a "proper" calibration is required or may prompt modification of the item's working spec as assigned by the user.

But what about conformance, especially regarding the meaning of a Certificate of Conformance ? Typically available when an instrument is purchased, it is now generally recognized that such a document has little value as an assurance of product performance. Of course, the manufacturer expects that the product conforms to its spec but, in this sense, the document simply affirms that the customer's purchase order/contract requirement has been duly fulfilled.

Hope this helps

Attaching another article which is worth reading

This is Hershal's (metrologist) comment on Calibration vs. Verification. (http://elsmar.com/Forums/showpost.php?p=203466&postcount=8) Then again it is the 'metrologist' language vs. common language. If we want to be technical, we should leave out common language.

With regards to the relevant clause in ISO 9001 on the need for calibration or verification, I think it simply means that both calibration (with a certificate issued by a lab and contain the necessary items like uncertainty) or verification (done in-house and with relevant procedures and records) are acceptable as evidence that the instrument had been checked for accuracy and cleared for used. The organization is ultimately responsible to determine if verification is good enough for their kind of operation/industry.

This is Hershal's (metrologist) comment on calibration vs verification. (http://elsmar.com/Forums/showpost.php?p=203466&postcount=8) Then again it is the 'metrologist' language vs common language. If we want to be technical, we should leave out common language.

With due (and ample) respect, Hershal's definitions are without normative provenance, which is a polite way of saying he's expressing an opinion.

With regards to the relevant clause in ISO 9001 on the need for calibration or verification, I think it simply means that both calibration (with a certificate issued by a lab and contain the necessary items like uncertainty) or verification (done in-house and with relevant procedures and records) are acceptable as evidence that the instrument had been checked for accuracy and cleared for used. The organization is ultimately responsible to determine if verification is good enough for their kind of operation/industry.

Again, no normative reference. How do you know that calibration is different from verification?

With due (and ample) respect, Hershal's definitions are without normative provenance, which is a polite way of saying he's expressing an opinion.

Again, no normative reference. How do you know that calibration is different from verification?

Jim, you had a good question for which I have no answer. Let's see what our metrologist friends have to add/say.

Not sure if this has evolved as :topic: or not... but I'll give it a shot.

I am not familar with the core-specification usage, but have seen the two words develop distinct differences in practice.

To me, calibration and verification are generally two levels of activity, with calibration being at a higher tier than verification (and for good reason). Calibration will always involve an uncertainty calculation, a calibration range, a tolerance, NIST traceable standards, and a pass/ fail assessment. Verification may not have any of the above points involved with it.

Thus, given the business application, a "calibration" activity may be performed, or a "verification" may be performed. In either, it is very clear on the documentation what the customer is getting.

However.... I have also seen widespread confusion in the use of these terms (and a few others). Thus, each organization should keep a calibration procedure of some sorts, and identify what activities are encompassed by the use of the word.

To me, calibration and verification are generally two levels of activity, with calibration being at a higher tier than verification (and for good reason). Calibration will always involve an uncertainty calculation, a calibration range, a tolerance, NIST traceable standards, and a pass/ fail assessment. Verification may not have any of the above points involved with it.

Brad,

You are right that these are 2 levels of activity but Verification is higher than Calibration as the pre-requsite for Verification is calibration should be successful (as per my attachment which I have done earlier).

As Harry said, we have to wait for Metrologists to get a clear picture. :yes:

Not sure if this has evolved as :topic: or not... but I'll give it a shot.

I am not familar with the core-specification usage, but have seen the two words develop distinct differences in practice.

To me, calibration and verification are generally two levels of activity, with calibration being at a higher tier than verification (and for good reason). Calibration will always involve an uncertainty calculation, a calibration range, a tolerance, NIST traceable standards, and a pass/ fail assessment. Verification may not have any of the above points involved with it.

Thus, given the business application, a "calibration" activity may be performed, or a "verification" may be performed. In either, it is very clear on the documentation what the customer is getting.

However.... I have also seen widespread confusion in the use of these terms (and a few others). Thus, each organization should keep a calibration procedure of some sorts, and identify what activities are encompassed by the use of the word.

Brad - widespread confusion is an understatement. For years, I've encountered people who 'talk' calibration, but it's clear they only have a scant understanding of the concepts and activities. You've captured the spirit of the message I was attempting to convey - thanks for that - and trying to help the OP with his dilemma.

I guess I could have used the analogy of verification being like figuring out if you feel/look well in the morning (checking out what you look like in the mirror, sticking your tongue out to see how furry it is:lol:) compared calibration being like going to the doctor's to get measurements made of your blood pressure, samples of blood taken for analysis etc.

Our aim here should be to clarify and attempt to answer the OP's questions, not automatic gainsaying.

Thanks, too to Qualityalways.

As Harry said, we have to wait for Metrologists to get a clear picture. :yes:

Brad - widespread confusion is an understatement.
<snip>
Our aim here should be to clarify and attempt to answer the OP's questions, not automatic gainsaying.


If there is widespread confusion, it's either due to the ambiguity of the standard, or the fact that people don't understand the concept of definition of key terms. I think in this case it's a combination of the two. When a word takes on meaning not present in its dictionary denotation, or widely accepted usage, it's incumbent upon the one using the deviated meaning to explain himself. We cover this in our documentation (or should) by providing definitions of key terms so as to avoid misunderstanding. The definitions then become normative, and we have a reference to use in settling disagreement.

No such normative definitions exist in the present case, as far as I know, which means that we shouldn't be deviating from standard usage. To do so is what causes confusion. The standard is at fault, imo, for appearing to differentiate between "calibration" and "verification" without further explaining the distinction between the two. Given no such normative reference, I will always defer to what we know the words to mean, and if I'm communicating with someone who might not understand what I'm saying, I'll make sure that I'm understood unambiguously.

While Hershal is high on my list of the Covers I respect the most, his considerable authority exists in metrology, not English usage, and I would have the same argument with him as with anyone else on this subject, if he disagreed.

I generally agree with Andy's contention that we should concentrate more on the OP's dilemma, but there are times when the question at hand gets answered, and in so doing more questions arise. Personally, I feel that I would be doing the Cove at large a disservice if when faced with a statement I believe to be wrong or misleading I don't attempt correction or clarification. I know the difference between gainsaying (to oppose by contradiction alone) and debate. There is nothing to be gained from the former, and much from the latter. For an illustration of the difference, I refer the reader to Monty Python's great sketch, The Argument Clinic (http://www.mindspring.com/%7Emfpatton/sketch.htm).

If there is widespread confusion, it's either due to the ambiguity of the standard, or the fact that people don't understand the concept of definition of key terms. I think in this case it's a combination of the two. When a word takes on meaning not present in its dictionary denotation, or widely accepted usage, it's incumbent upon the one using the deviated meaning to explain himself. We cover this in our documentation (or should) by providing definitions of key terms so as to avoid misunderstanding. The definitions then become normative, and we have a reference to use in settling disagreement.

No such normative definitions exist in the present case, as far as I know, which means that we shouldn't be deviating from standard usage. To do so is what causes confusion. The standard is at fault, imo, for appearing to differentiate between "calibration" and "verification" without further explaining the distinction between the two. Given no such normative reference, I will always defer to what we know the words to mean, and if I'm communicating with someone who might not understand what I'm saying, I'll make sure that I'm understood unambiguously.

While Hershal is high on my list of the Covers I respect the most, his considerable authority exists in metrology, not English usage, and I would have the same argument with him as with anyone else on this subject, if he disagreed.

I generally agree with Andy's contention that we should concentrate more on the OP's dilemma, but there are times when the question at hand gets answered, and in so doing more questions arise. Personally, I feel that I would be doing the Cove at large a disservice if when faced with a statement I believe to be wrong or misleading I don't attempt correction or clarification. I know the difference between gainsaying (to oppose by contradiction alone) and debate. There is nothing to be gained from the former, and much from the latter. For an illustration of the difference, I refer the reader to Monty Python's great sketch, The Argument Clinic (http://www.mindspring.com/%7Emfpatton/sketch.htm).

Hello Jim,

Monty Python, The Argument Clinic: y05EmK66Gsk

Enjoy!

Stijloor

I came across his interesting 'old' thread (http://elsmar.com/Forums/archive/index.php/t-3905.html) where the same subject was discuss at length and noted several good post, in particular the one by Graeme (C. Payne) dated 26th Dec 2000 @ 9.24pm where he provided sources for the definition of 'calibration'.

Reference:
International vocabulary of basic and general terms in metrology (ISO, 1993):
"A set of operations that establish under specified conditions the relationship between values of quantities indicated by a measuring instrument or measuring system, or values represented by a material measure or a reference material, and the corresponding value realized by a standard.
Notes: 1. The result of a calibration permits either the assignment of values of measurands to the indications or the determination of corrections with respect to indication.
2. A calibration may determine other metrological properties, such as the effect of influence quantities.
3. The result of a calibration may be recorded in a document, sometimes called a calibration certificate or a calibration report."

The definition above is included by reference in the new ISO/DIS 9000 and ISO/IEC 17025:1999, and is included verbatim -- but without the notes -- in ISO 10012-1:1992 and ISO 10012-2:1997. An essentially identical definition in the United States is in ANSI/NCSL Z540-1:1994; the only substantial difference is the addition of one note relating to calibration factors and curves. Essentially identical definitions are also in other sources, notably the NCSL Recommended Practice 1 on calibration intervals.

In addition to the essential core of calibration (above) most technical definitions in the United States do include the concept of adjusting an instrument, usually as one of several possible actions. Some international standards also include this. Almost all calibration laboratories will, as part of the added value of the calibration process, adjust an out-of-tolerance instrument. (Personally, I would not use one that does not - and all of the labs I have worked with do adjust instruments.) However desirable, though, adjustment is not an essential part of "calibration" as defined by ISO.

The most common additional definition in the United States is:
"the comparison of measuring and test equipment or measurement standard of unknown accuracy to a measurement standard of known accuracy in order to detect, correlate, report, or eliminate by adjustment any variation in the accuracy of the instrument being calibrated."

This or essentially similar definitions appear in a number of US references: NCSL Recommended Practices 2 and 3; MIL-STD-1309D; MIL-STD-45662A (canceled in 1994); NIST Special publication 260-100; ANSI/ASQC M1-1987. A similar definition appears in ISO 10012-1:1992 and ISO 10012-2:1997 under the label "metrological confirmation". Note, though, that the core concept is still comparison of a measuring instrument to a standard, just as in the ISO definition. "Adjustment to remove variation" is simply one of several actions that may be taken. Therefore, my earlier message was incorrect to this extent, because in that I was referring only to the ISO definition which does not include any of the actions that result from the comparison.

In the actual practice of calibration laboratories I have worked in and with for may years, the generalized calibration work process flow looks something like this --
Start
Compare the instrument under test to a measurement standard. ("calibrate" it.)
If the performance is within specifications,
Report the results and return the instrument to the customer.
Otherwise,
Report the out-of-tolerance condition to the customer.
If the instrument can be adjusted to meet specification,
Adjust the instrument in conformance to lab policy.
Go back to start.
Otherwise
Consult the customer and lab policy for appropriate action.
If the instrument is repaired, go back to start.
End

It confirms Herhal's comment that to be classified as 'calibration', there must be an unbroken chain of traceability + uncertainty calculations. Without any of the two, it is verification.

I came across his interesting 'old' thread (http://elsmar.com/Forums/archive/index.php/t-3905.html) where the same subject was discuss at length and noted several good post, in particular the one by Graeme (C. Payne) dated 26th Dec 2000 @ 9.24pm where he provided sources for the definition of 'calibration'.

It confirms Herhal's comment that to be classified as 'calibration', there must be an unbroken chain of traceability + uncertainty calculations. Without any of the two, it is verification.

Harry,

The words "traceability" and "uncertainty," or any form of them, appear nowhere in the text you quoted. Nor is there anything in the text that says anything about "verification."

"A set of operations that establish under specified conditions the relationship between values of quantities indicated by a measuring instrument or measuring system, or values represented by a material measure or a reference material, and the corresponding value realized by a standard.
Notes: 1. The result of a calibration permits either the assignment of values of measurands to the indications or the determination of corrections with respect to indication.
2. A calibration may determine other metrological properties, such as the effect of influence quantities.
3. The result of a calibration may be recorded in a document, sometimes called a calibration certificate or a calibration report."

I am not a Metrologist but will attempt to link your queries, Jim.

When we talk about a standard in 'measurement' context, it refers to the SI unit. Traceability is just that process to show that the master you used can be linked to the SI.

When we talk about uncertainty, we are referring to the influence of many factors such as temperature, moisture etc and they are collectively referred to as influence quantities.

I am not a Metrologist but will attempt to link your queries, Jim.

When we talk about a standard in 'measurement' context, it refers to the SI unit. Traceability is just that process to show that the master you used can be linked to the SI.

Not true at all, unless (and I know I'm repeating myself) there is a normative reference. A "standard" can be whatever two or more people agree on, and might have nothing to do with SI units.

When we talk about uncertainty, we are referring to the influence of many factors such as temperature, moisture etc and they are collectively referred to as influence quantities.
Influence factors contribute to, but are not the same as, uncertainty. I repeat: there's nothing in the text you quoted that supports the conclusions you derived from it.

Yes, those were my interpretations based on reading in between the lines and my understanding of the subject.

In other words, you are looking for a specific document with all these words explained (when you talk about normative reference) so that others do not need to guess what it means. I am not sure if such a document exists?

What about definitions by and found in 'NIST' documents? Do you or can you accept them as 'the' interpretation?

Calibration vs. Verification - A Good List of Definitions (http://elsmar.com/Forums/showthread.php?t=945)
Calibration vs. Verification - ANSI/NCSL/Z540 - Definitions of (http://elsmar.com/Forums/showthread.php?t=938)
Calibration vs. Verification - Definition of (http://elsmar.com/Forums/showthread.php?t=3905)
Verification vs. Validation vs. Calibration - What is the difference? (http://elsmar.com/Forums/showthread.php?t=12703)
Calibration? Verification? Is this a calibration? (http://elsmar.com/Forums/showthread.php?t=14849)
What is the difference between in house calibration and verification? (http://elsmar.com/Forums/showthread.php?t=21242)
Definition of Calibration (http://elsmar.com/wiki/index.php/Calibration)

The question here should be qualified to be:

Calibration vs. Verification of Calibration.

Calibration vs. Verification - A Good List of Definitions (http://elsmar.com/Forums/showthread.php?t=945)
Calibration vs. Verification - ANSI/NCSL/Z540 - Definitions of (http://elsmar.com/Forums/showthread.php?t=938)
Calibration vs. Verification - Definition of (http://elsmar.com/Forums/showthread.php?t=3905)
Verification vs. Validation vs. Calibration - What is the difference? (http://elsmar.com/Forums/showthread.php?t=12703)
Calibration? Verification? Is this a calibration? (http://elsmar.com/Forums/showthread.php?t=14849)
What is the difference between in house calibration and verification? (http://elsmar.com/Forums/showthread.php?t=21242)
Definition of Calibration (http://elsmar.com/wiki/index.php/Calibration)

The question here should be qualified to be:

Calibration vs. Verification of Calibration.

Hi Marc,

Thank you for the links to similar threads.
Proof that history repeats itself. For an excellent reason though...;)

But I'm concerned that some Covers get too carried away with semantics..:frust::frust:

Stijloor.

Marc's posted reminded me of my Dad..."If I have to come upstairs one more time to quiet you kids down, I'll..."

Thanks Marc.

Yes, those were my interpretations based on reading in between the lines and my understanding of the subject.

In other words, you are looking for a specific document with all these words explained (when you talk about normative reference) so that others do not need to guess what it means. I am not sure if such a document exists?

What about definitions by and found in 'NIST' documents? Do you or can you accept them as 'the' interpretation?


I think we could benefit from a review of the question at hand, and some explanation on my part. I know that many here probably think I'm being nit-picky and pedantic, but...

Here is the original statement (http://elsmar.com/Forums/showthread.php?p=206388#poststop) from AndyN, which has now been split from this thread (thanks, Brad :agree1:):
... if anyone is making decisions about product or process 'acceptability' (does it meet a specification), then the equipment used should be calibrated or at least verified as operating correctly.My response was
"Calibrated" and "verified as operating correctly" are the same thing.ISO 9001-2000 (7.6)says that measurement devices used in making decisions must be
calibrated or verified at specified intervals, or prior to use, against measurement standards traceable to international or national measurement standards...Note that (A) there is no explanation of the difference between "calibrated" and "verified" in the standard (or any reference I know of) and (B) in either case, it says that standards must be traceable.


Thence opened the floodgates. :mad::D

This all has to do with definition of terms and normative references; both ideas are fundamentals in our profession. Ironically though, they seem to be among the most widely misunderstood or overlooked concepts. It boils down to this: if you use terms in your documentation (and this applies to everyone, including ISO) that may be subject to more than one definition, you must provide a definition that becomes the "court of last resort." That's what a "normative reference" is. If I provide a definition of a term in my quality manual, and the manual is duly approved, everyone else in the company is enjoined from creating their own definitions or interpretations regardless of any commonly-accepted denotations. Dictionary denotations should be deviated from only when absolutely necessary, but when it's important that everyone singin' from the same hymnal, you do what you have to do to maintain clarity and order.

In the present case, insofar as the ISO-9001-2000 is concerned, "calibrated" and "verified" both unambiguously mean that applicable devices must be compared to a traceable standard. Anyone who disagrees with this is reading something that ain't there. Furthermore, ISO provides no normative reference which would lead us to believe that there is a substantive difference between calibrating a device against a traceable standard and verifying a device against a traceable standard. Furthermore, we know (or at least I hope we know) that calibration is nothing more than the act of comparing something (anything, not just a measurement device) to a standard. ISO-9001 expands the definition slightly to require traceability of the standard(s) used, but that expansion also applies to "verified."

Now--if someone can supply a traceable :cool: normative reference that contradicts what I've said, I will gladly concede the matter and feel better for having learned something. When I say a traceable normative standard, I mean one for which an unbroken trail exists between ISO-9001-2000 and the definitions. I'm not looking for someone's personal interpretation or opinion; this is a matter of black-and-white.

Finally, a word about why it's worth making an issue over something like this. This is a widely-referenced forum, and beyond terrific group of people we've come to know and respect, many people who never register and never post look to it for information. For all of us who post regularly, we need to do our best to make sure that the most accurate information possible is presented. Errors need to be corrected when they pop up in order to maintain the integrity of the system. There is nothing personal in this. I've made mistakes myself; we all do from time to time. But we owe it to everyone who comes here to do our best to make sure we provide good advice. :D

Thanks for your post, Jim. We (or at least I) learned not to assume things.

Perhaps you would like to look at this link (http://www.ntmdt.ru/download/vim.pdf) for a draft copy of 'International vocabulary of basic and general terms in metrology (VIM)'. Definitions of calibration, verification and validation (as in ISO 9001) are given therein (page 20-22). I do not think there are much changes in the final copy.

From Harry's Link above:

(From 2.27 verification)
"NOTE
Verification should not be confused with calibration of a measuring system, or vice versa." :confused:


Ok - how about real world examples:

1. I use the services of a 17025 lab to calibrate my analytical scales using NIST traceable weights.
Q. This can be referred to as either calibration or verification?

2. I buy a set of NIST traceable weights to "check" my scales in between calibrations/verifications from #1 above.
Q. What is this called?

3. I buy/use a set of weights that are not traceable to NIST for use as an operator check in between whatever we call #2 above.
Q. What is this called?

Calibration vs. Verification - A Good List of Definitions (http://elsmar.com/Forums/showthread.php?t=945)
There are no normative definitions given in this link, and its definition of "verification" seems to indicate that calibration is a form of verification.
Calibration vs. Verification - ANSI/NCSL/Z540 - Definitions of (http://elsmar.com/Forums/showthread.php?t=938)
This one is mostly a discussion of the meaning of "calibration," and whether or not "calibration" necessarily includes adjustment. I think we've agreed that it doesn't.
Calibration vs. Verification - Definition of (http://elsmar.com/Forums/showthread.php?t=3905)I didn't read the whole thread, but there doesn't seem to be anything that authoritatively addresses the question at hand. There's some interesting conversation, but no real meat. At one point, one person provides yet another unfounded definition for "verification": Verification is the act of using the data from calibration (or in-service check) to determine suitability for a task.
Verification vs. Validation vs. Calibration - What is the difference? (http://elsmar.com/Forums/showthread.php?t=12703)
This conversation is mainly about validation vs. calibration.
Calibration? Verification? Is this a calibration? (http://elsmar.com/Forums/showthread.php?t=14849)
More interesting discussion, with one Cover providing his own definition of verification, without normative reference.
What is the difference between in house calibration and verification? (http://elsmar.com/Forums/showthread.php?t=21242)This thread generally treats calibration and verification as synonymous.
Definition of Calibration (http://elsmar.com/wiki/index.php/Calibration)
I don't think the definition of "calibration" is in question.

The question here should be qualified to be:

Calibration vs. Verification of Calibration.
All due respect, but the question is, "For the purposes of ISO-9001-2000, is there a substantive, defined difference between "calibrated" and "verified?"

Thanks for your post, Jim. We (or at least I) learned not to assume things.

Perhaps you would like to look at this link (http://www.ntmdt.ru/download/vim.pdf) for a draft copy of 'International vocabulary of basic and general terms in metrology (VIM)'. Definitions of calibration, verification and validation (as in ISO 9001) are given therein (page 20-22). I do not think there are much changes in the final copy.

Thanks for the link, Harry. It seems to be a step in the right direction, but the definition given for "verification" which is
confirmation through examination of a given item and provision of objective evidence that it fulfils specified requirements
seems to aptly describe the calibration process, but then we're warned in a note that...
Verification should not be confused with calibration of a measuring system, or vice versa.
EXAMPLES
a) Demonstration that a given reference material as claimed is homogeneous down to samples having a mass of 10 mg for the quantity and measurement procedure concerned.
b) Demonstration that stated performance properties of a measuring system are achieved.
The examples given aren't particulary helpful; what they seem to be saying is that calibration is a form of verification, and vice-versa, but don't call calibration "verification," and vice-versa. :confused:

The following is a word for word reproduction of the definition from VIM

2.22 Calibration – definition (a) – { definition (b) for IEC related matters}

Operation establishing the relation between quantity values provided by measurement standards and the corresponding indications of a measuring system, carried out under specified conditions and including evaluation of measurement uncertainty.

Notes 1: the relations referred to in definitions (a) and (b) can be expressed by calibration diagrams, calibration function, or calibration tables.


2.27 Verification

Confirmation through examination of a given item and provision of objective evidence that it fulfils specified requirements.

Note: verification should not be confused with calibration of a measuring system, or vice versa.

To me, the obvious difference is that calibration need to be carried out under specified conditions and includes evaluation of measurement uncertainty.

Uncertainty is in turn an essential part of traceability. Without the measurement uncertainty part, the traceability chain is broken (even if all the other essential components that contribute to traceability remain the same).

Can we now safely conclude that the key difference between calibration and verification is the need for determination of measurement uncertainty.

Thanks for the link, Harry. It seems to be a step in the right direction, but the definition given for "verification" which is..........

seems to aptly describe the calibration process, but then we're warned in a note that...

:

I can see your point, Jim and I do agree. Any attempts to carry out calibration in an 'uncontrolled' or non-specific condition automatically becomes verification because you would not be able to provide the uncertainty part. In that sense you are right that the physical part (of carrying out the comparison) is the same.

Perhaps that's the reason, ISO came out with their guidelines in an attempt to differentiate the two.

Interesting thread.

If I may throw another semantic spanner in the works - if you ever see the word check in an ISO standard it will be officially translated as verification in French. So in ISO-speak verification = check. Unfortunately it adds nothing to the debate about real-world meanings of verification/check, but just my two pence worth.

I know that many here probably think I'm being nit-picky and pedantic, but...
How did you know? You can read minds, too!! :mg:



This all has to do with definition of terms and normative references; both ideas are fundamentals in our profession. Ironically though, they seem to be among the most widely misunderstood or overlooked concepts. It boils down to this: if you use terms in your documentation (and this applies to everyone, including ISO) that may be subject to more than one definition, you must provide a definition that becomes the "court of last resort." That's what a "normative reference" is. If I provide a definition of a term in my quality manual, and the manual is duly approved, everyone else in the company is enjoined from creating their own definitions or interpretations regardless of any commonly-accepted denotations. Dictionary denotations should be deviated from only when absolutely necessary, but when it's important that everyone singin' from the same hymnal, you do what you have to do to maintain clarity and order.


I completely agree:agree1:, and as usual, well stated and well written on your part. Whether we come to complete agreement or not on the use of the words here at the Cove, in the trenches this discussion is not of much value. Each quality system must be clear on the terms and actions being utilized. Every person here should be able to walk in to someone’s process and understand clearly what each activity encompasses, and the differences among them (given proper definitions in their documentation).


In the present case, insofar as the ISO-9001-2000 is concerned, "calibrated" and "verified" both unambiguously mean that applicable devices must be compared to a traceable standard. Anyone who disagrees with this is reading something that ain't there. Furthermore, ISO provides no normative reference which would lead us to believe that there is a substantive difference between calibrating a device against a traceable standard and verifying a device against a traceable standard. Furthermore, we know (or at least I hope we know) that calibration is nothing more than the act of comparing something (anything, not just a measurement device) to a standard. ISO-9001 expands the definition slightly to require traceability of the standard(s) used, but that expansion also applies to "verified."


This is where I feel the need to provide a possibly different light. Yes, I have been educated about the use of verification as related to ISO-9001-2000 and respect that view. However, the road of life is paved with good intentions. Even among widely respected references, there is still debate and confusion. That is NOT to suggest that the fight for consistency is to end, we all pack up our bags and go home. Rather, it is to acknowledge the difference exists, and they need to be respected.

My earlier post on this subject referred to verification as a lesser to calibration. However, I qualified the difference and my use of the term. My point is this: We may have to determine the poster’s (and each other) point of reference first. While it should be an identified reference, it may be something else, which may include operationally defined actions in a procedure, industry/cultural norms, possible craft-driven vocabulary, and possibly a complete lack of understanding.



Finally, a word about why it's worth making an issue over something like this. This is a widely-referenced forum, and beyond terrific group of people we've come to know and respect, many people who never register and never post look to it for information. For all of us who post regularly, we need to do our best to make sure that the most accurate information possible is presented. Errors need to be corrected when they pop up in order to maintain the integrity of the system. There is nothing personal in this. I've made mistakes myself; we all do from time to time. But we owe it to everyone who comes here to do our best to make sure we provide good advice.

I agree:agree1:. My thoughts are that we need to come up with some definitions that maybe we all agree with here, first. While that may not be an ideal normative reference, it is still a reference where we can work together. That way, we don’t frustrate each other as to the meaning of calibration, verification, etc.

Also, just so the holding hands/singing at the campfire side of me gets to speak: let’s always remember to develop understanding first. I think it would behoove the first on-site posters to elicit understanding on the part of the OP about the terms. IMHO, some of the posters here are not that concerned with the semantics of words; they’re just trying to keep their jobs. I am NOT excusing improper use of words, etc.; rather, in the light of Maslow’s Hierarchy of needs, we should address their primary need first. Other items can come later.

I think when I offer something, I might need to beef up my terms (with more details) like verification, so it’s not misunderstood. I will try to be a bit more sensitive to that.

Thanks for the link, Harry. It seems to be a step in the right direction, but the definition given for "verification" which is

seems to aptly describe the calibration process, but then we're warned in a note that...

The examples given aren't particulary helpful; what they seem to be saying is that calibration is a form of verification, and vice-versa, but don't call calibration "verification," and vice-versa. :confused:

Please allow me to disagree with you Jim.I am refering to your comments w.r.t. ISO VIM (Thnx to Harry) P20- 2.27'....what they seems to be saying...'
Well,the words have exact meaning in the context they are used,and they exactly mean what they say.
"VERIFICATION SHOULD NOT BE CONFUSED WITH CALIBRATION
OF A MEASURING SYSTEM or vice versa"
I don't find any ambiguity in the stated sentence.It is communicating loud and clear.This leaves no room for doubt,that both these words have different
usage in the current context,and we must not mix them up.
I am following this enlightening thread from the begining,and all the areas of their meaning are amply discussed,by distinguished personalities,not leaving room for adding anything unsaid.Yet I'd like to throw some more light,in the hope this may help.

'Verification' is a word having a wide spectrum of usage,legality being an important field.
'Calibration' has a limited usage,chiefly used for measuring instruments.

While calibrating,you are verifying that the reading of instrument being calibrated conform to the master.

In 'Verification' you are not always caibrating.May be you are verifying a document or a fact or taking oath etcetra.

In other words,you are verifying when you are calibrating,but you may not be calibrating when you are veryfying!
Like:'All the genius are mad,but all the mad are not genius.'
Then how can we say that Calibration and Verification are the same thing?!

Umang :cool:

It becomes the same topic as calling an item a "Fixture" or a "Gage". At my company, I defined a Gage as an item that actually provides a measurment output that is is used to determine conformance to customer requirments. I have seen way too many people waste a significant amount of money on the Calibration of "Fixtures" - ie ; Staging Blocks etc. - these Fixtures are part of the measurement system when used in tandem with something that actually gives the OUTPUT - but, if the auditor would like to pay to "calibrate" a staging block, I'll send him the bill, hence, Calibrate one and verify that the other is the prescribed method to be utilized. Make the standard work for you - this is not about creating busy-work for someone to do all day, it is about adding value to a process.

It becomes the same topic as calling an item a "Fixture" or a "Gage". At my company, I defined a Gage as an item that actually provides a measurment output that is is used to determine conformance to customer requirments. I have seen way too many people waste a significant amount of money on the Calibration of "Fixtures" - ie ; Staging Blocks etc. - these Fixtures are part of the measurement system when used in tandem with something that actually gives the OUTPUT - but, if the auditor would like to pay to "calibrate" a staging block, I'll send him the bill, hence, Calibrate one and verify that the other is the prescribed method to be utilized. Make the standard work for you - this is not about creating busy-work for someone to do all day, it is about adding value to a process.


Hello pudge! What a great first post! Welcome to the Cove! You make some good points here, and we sure look forward to your continued input.

Also, just so the holding hands/singing at the campfire side of me gets to speak: let’s always remember to develop understanding first. I think it would behoove the first on-site posters to elicit understanding on the part of the OP about the terms. IMHO, some of the posters here are not that concerned with the semantics of words; they’re just trying to keep their jobs. I am NOT excusing improper use of words, etc.; rather, in the light of Maslow’s Hierarchy of needs, we should address their primary need first. Other items can come later.
Pardon my tardiness in responding, but I've been in the hospital with a GI issue this week.

I think I agree with you; I often ask people for clarification before offering an opinion. In this case, the thread has been split, and I think that the OP got a reasonable range of responses before the side-discussion began. We have to ask people to clarify their questions for two primary reasons: language issues (people for whom English is not the native language) and people who, as you put it, "...are not that concerned with the semantics of words." In other words, lack of concern about being understood. At least part of my purpose in igniting starting the discussion was to point out the fact that if you want other people to understand what you're trying to say, you had better be concerned about "the semantics of words."