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Canada's NRC on Traceability

Updated: Jul 5, 2022

Defence lawyers need to convince the criminal justice system that "traceability" of all forensic measurements is a condition precedent to reliability. What does "traceability" mean and is it part of Canadian criminal law? What does the Canadian scientific community have to say about "traceability"?


Why is the establishment of "calibration intervals" required to maintain "traceabilty"?


Are "étalon" and "norme" the same thing? Are these concepts easier to understand in French? When we talk about a "standard" in english do we mean a "norme" or an "étalon"?


Purpose:


To establish that "traceability" is a scientific concept used in Canada.


To define "traceabilty" in a Canadian context.


To establish that "calibration interval" is a scientific concept used in Canada.


To explain the two English meanings of "standard" by reference to the difference in French between "etalon" and "norme" in the NRC document in English and French.

[Sample excerpt of a cross-examination of a Crown expert]


MR. BISS: Q. And sir, you are familiar with the National Research Council of Canada.


A. Yes.

Q. The National Research Council of Canada publication on recommended practices for calibration laboratories. Are you familiar with this document?


A. No, it’s the first time I’m seeing this.

Q. All right. I just want to go down at the bottom of the page under the word ‘traceability’. Traceability is referred to as “the property of the result of the measurement or the value of the standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties.” Now is that consistent with your understanding of what traceability is?


A. Yes.

Q. And turning to page – actually, item 6.2, Traceability of Measurements. It says, “Reference standards of measurement, reference materials and all measurements made by the laboratory should be traceable through appropriate designated standards.” Is that consistent with your experience and is that consistent with other scientific literature on good management – good measurement practice?


A. Yes.

Q. And down at the very bottom of the page under 6.8 Intervals of Calibration, it says “Test equipment and measurement stand should be calibrated at periodic intervals, established and maintained to assure acceptable measurement uncertainty and reliability. Now is that statement consistent with the scientific literature that you’re familiar with related to good measurement practice?


A. Yes.


MR. BISS: If that item might be marked as anexhibit please, Your Honour?


THE COURT: Yes, Exhibit 30, National Research

Council Canada, Recommended Practices for Calibration Laboratories. EXHIBIT NUMBER 30: National Research Council Canada, Recommended Practices for Calibration Laboratories – produced and marked.


MR. BISS: Q. And I’m just going to – I think maybe ultimately this could be attached to it, the same one, but just look at the French language version of the same thing. I just want to refer you sir.... A. I won’t be able to translate it. Q. Well, I’m not asking you to do that. A. Okay.

Q. But if we look at some of the same sections I just – I just want to look under 3.0 Definitions at the bottom of the page. A. All right. Q. All right, “étalon des mesures,” it’s interesting, the National Research Council uses that same expression of an “étalon des mesures.” Do you see that? And then later on, “étalon des mesures, [indiscernible].” A. Yes. Q. That would be the French version. A. Yes. Q. Now, I want to suggest to you that that is a reference to specifically a measurement standard which is different than a recommended standard in principle. They’re two different things in science. The idea of a recommended standard, the French equivalent would be a “norme” is something completely different from an “étalon des mesures” for a measurement standard. A. Sorry, can you repeat that? You’ve lost me.


Q. I want to suggest to you that in science... A. Yes. Q. ...that the concept of a recommended procedure, a recommended norm, recommended standards and procedures, is a completely different concept than the thing


that is used as a reference measure. And even though in English we often use the same word ‘standard’ to describe both things, they’re – the two concepts are completely different in science. A. I’m still having difficulty following that whole line of.... Q. Well, it’s important to you as a scientist.... A. This should be a French translation of the English that’s on the English document. Q. But the – the English terminology, if you still have that... A. Yes. Q. ...document in front of you. A. Measurement standard. Q. Measurement standard. But the measurement standard that’s referred to there is obviously not a recommended standard that they’re talking about. They’re talking about something that is reference material, that is a thing that can be traced back to some higher level of authority in the calibration hierarchy. It is reference material. A. Yes. That word is listed in the English version. MR. BISS: If that document might be marked as an Exhibit Your Honour. THE COURT: Just hang on a second. What am I going to do with this document in French? What’s the import of – if you’re going to reference this in a way that I can use it, being a unilingual judge, what am I to make of it? What’s – what’s the distinction that


you’re endeavouring to elicit from the French version as opposed to the English, and why is the English not determinative of the issue as opposed to the interpretation in French which you suggest constitutes a significant difference, I gather? MR. BISS: Well, no I’m not saying that the two documents are different. I’m just simply saying that it is clear that the National Research Council in its document in English, when it says Measurement Standard, it’s not talking about a recommended standard. It’s talking about reference material. THE COURT: Right, but you’re interpreting the import of the English version based on reference to the French, correct? MR. BISS: Yes. THE COURT: Well, you’ve got to have this translated though, or what am I to make of it? MR. BISS: All right. THE COURT: So.... MR. BISS: Then, Your Honour, I will not ask you to.... THE COURT: If you – you must – you’re bilingual I gather? Are you? MR. BISS: No. But I do my best. THE COURT: Right. We’ll you’re – you have some facility in French. I don’t think it’s even – I appreciate our witness has a French name, and I’m assuming can speak French as a consequence. Maybe you’re making the same


assumption, but he’s referenced that he


couldn’t translate this, so I – I don’t think we can rely on it MR. BISS: All right, I’ll then withdraw my request that that document... THE COURT: Okay. MR. BISS: ...be made an exhibit, Your Honour. THE COURT: I’m sorry that I can’t assist, but I don’t think either of us are equipped to really assist. So.... A. No, Your Honour, I can’t. MR. BISS: Thank you Your Honour. THE COURT: Okay. MR. BISS: All right, so but the English version would be Exhibit.... THE COURT: Yeah, the English version is Exhibit 30. I think we’ve attended to that one. MR. BISS: All right.

[See the explanation in the VIM section 5.1 in note 8 respecting this distinction]

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