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Each Test Stands on Its Own

Updated: Oct 10, 2022

Sample cross-examination on the ATC and CFS Position Paper policy that every test stands on its own - that "reliability" has nothing to do with tests or data before or after the subject tests.

Purposes of this cross-examination:

To challenge the ATC hypothesis or policy that "each test stands on its own".

To identify the hypothesis as faith or policy, not scientific opinion.

To demand the wording of the hypothesis and the empirical testing methodology if it is a scientific opinion.

To identify exactly what other anchoring information ATC/CFS considers essential to reliability notwithstanding this sweeping statement.

To identify exactly what other information they label irrelevant.

To obtain an admission that this is not scientific opinion.

To educate the Court as to the difference between scientific opinion and technical opinion.

To separate the difference between a priori logical opinion and an opinion based on empirical science.

To identify the lack of empirical studies using "sampling" of aging instruments in the field.

To establish that the ATC Position Paper is not a consensus document generally accepted by all forensic toxicologists.

To introduce the concepts of "metrological control" and "metrological supervision" to the Court.

Canadian Society of Forensic Science CSFS journal

A. You need to look at that information for the

purposes of the breath test that was done in that particular

case. It's irrelevant to the test that was done in this


Q. Now, that concept, that every test stands on

its own, that's not a statement of scientific opinion; that's

a statement of policy?

A. Sorry, a statement --

Q. Your evidence in-chief...

A. Yes.

Q. ...was that every subject test stands on its


A. Correct.

Q. That's a statement not of scientific opinion,

it's a statement of policy?

A. It's a scientific opinion, not policy.

Q. All right. How can that opinion be stated as

a hypothesis and tested? 1.

A. So as I've said previously, each test is

separate and independent, so there's a particular breath test

sequence that occurs for a particular subject test, right?

When that subject test is over, nothing else that happened at

other times has an effect on that test. What happened and

what effects that test, whether it's radio frequency

interference, ambient alcohol, mouth alcohol, or any other

number of messages, is relevant to that test at that time.

And, again, the next test is conducted, again, at a random

moment in time, and you have two tests that, according to the

recommendations, is that the two tests have to be within good

agreement and within 20 milligrams of alcohol in 100

millilitres of blood. Again, that increases the scientific

confidence in the reliability of the results.

Q. My suggestion to you is that that's a

statement of policy.

A. It's a recommendation at the Centre of

Forensic Sciences and the Alcohol Test Committee. It's

clearly in all those documents.

Q. It's a statement of policy by the Alcohol Test

Committee and by the Centre of Forensic Sciences, it's not a

scientific opinion.

A. It's a scientific -- scientifically

established parameter that has been in use long before I was

a forensic toxicologist.

Q. It's a guideline, it's a protocol, but it's

not a scientific opinion.

A. It's a recommendation based on science.

Q. And how would one -- if it is based on

science, how could that statement be expressed as a

scientific hypothesis and tested?

A. I can't think of a way to do that right now.

Q. You see, my suggestion to you is that it may

be a very, very good technical recommendation in an ordinary

case, where everything else is working normally, where the

police are following all the other recommended practices. It

may be a good approach, a good standard operating procedure,

if you will, but it is not a scientific opinion. It is not

an opinion that can be stated as a hypothesis and tested.

A. I would disagree with you. There are numerous

papers that's have been published by respected authors who

have said that two tests that don't differ by a particular

parameter, that are taken within a certain period of time and

considered to be in good agreement, is scientific reliability

and accuracy of the readings that were obtained at that time.

Q. Conclusive --

A. From the United States and Canada.

Q. Conclusively. Not just as a general

guideline, but that it is a conclusive determination

scientifically. Where's the empirical authority for saying


A. Again, because you have tests that are taken

at random moments in time, and the likelihood of one --

something happening on one test is possible, but the

likelihood of anything happening to two tests at two random

moments in time is so unlikely as to be a impossible. And


Q. So your first...

A. ...the basis for that.

Q. So you're expressing that statement as a

matter of logic, not as a matter of scientific opinion that

is testable.

A. I'm not sure how you would be able to test


Q. Well, let me just give you some possibilities.

A. All right.

Q. One possibility might be for the Centre of

Forensic Sciences or the Alcohol Test Committee, or somebody

in the system, to collect together to sample - I think you

know what I mean by sample - to sample some aging instruments

that are out in the field and bring them in and do empirical

testing and see if this what I suggest is a policy,

empirically works or whether it does not work. That would be

one methodology that might be attempted in order to check

whether or not this what I am suggesting is a statement of

policy, holds scientifically in empirical testing.

A. The proper working order of an instrument is

determined at the time of testing.

Q. Well, I understand that's the policy of your


A. Recommendations. You keep saying "policy".

They're recommendations. The Alcohol Test Committee's

recommendations. The manual that the Centre of Forensic

Sciences has produced is recommendations, not policy.

Q. But not every scientist who is a member of the

Canadian Society of Forensic Sciences agrees with that

policy. They say that there are gaps in it.

A. If you would like to provide me with a list of

those people, I can review that list.

Q. Well, we...

A. But the authoritative bodies in Canada agree

with those recommendations...

Q. We saw...

A. ...and that includes Ontario and Canada.

Q. We saw in Exhibit 17 and then 17B - those were

the exhibits - they were the correspondence between

Mr. Kupferschmidt and the editor of the Canadian Society of

Forensic Science Journal?

A. Yes.

Q. And Mr. Kupferschmidt said that there are

problems with the policy, and one of the big problems is that

there is no entity that is out there that is supervising the

police in terms of metrological control. I don't know

whether he used the words "metrological control". But he

said that there's no body that's out there that's supervising

the police to make sure that they are following the best

practices of the Alcohol Test Committee.

A. That's correct, yes.

Q. So there are scientists that are out there

that disagree with the policy that you can determine

everything on the basis of just the subject test and the data

that comes out of the subject test, right?

A. You've given me the name of one individual.

Q. Well...

A. And there's always going to be experts out

there who disagree with what is going on there, what's going

on in the breath program, what's being done with respect to

breath testing and instruments and the reliability.

Q. But my suggestion to you is, there are no

empirical studies out there. I mean, if I look through the

Wigmore book again that you referred to on the previous


front cover to Wigmore on Alcohol
Front cover to an excellent book on studies related to alcohol and impairment - by James C. Wigmore - see

A. Yes.

Q. Everything that we would ever want to know

about alcohol testing. It's filled with empirical studies,

including some of your own.

A. Yes.

Q. There's no empirical study in that book, or

anywhere else out there, that suggests that you can

scientifically close the door on problems with accuracy and

precision by conducting just a single pair of subject tests,

following the rules that you have outlined.

A. The program that's in place is fit for its

purpose, it works well, and that's all I can... I mean, we

can continue to argue about this point forever, but we

disagree -- we agree to disagree.

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