#controltest

BAC Analysis in a Lab Without Bracketing Controls is at Best Qualitative not Quantitative

Apr 27, 2018
4 min

BAC Analysis in a Lab Without Bracketing Controls is at Best Qualitative not Quantitative

We have a serious problems in the Canadian criminal justice system. One of them is the failure of Parliament and the Courts to recognize the differences between a qualitative measurement (a screening device result like a rapid home use COVID test kit or a roadside breath ASD, PBT, or ADSE tester result) and a quantitative measurement that results in criminal law sanctions. The Criminal Code and our case law, to some extent recognize the differences between an approved instrum

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Relevance of Contemporaneous Documentation by Inspector Taking Instrument Out of Service

Stephen Biss

Apr 20, 2018
4 min

Relevance of Contemporaneous Documentation by Inspector Taking Instrument Out of Service

Let's suppose that as a result of a disclosure request or Freedom of Information application you find an electronic or paper document that has an entry like this one on 5/20/2015. Should you go further and seek disclosure of the police notes, checklists, and instument printouts related thereto? Are they relevant (see Vallentgoed and Gubbins) to the reliability of a measurement result obtained a few days before 5/20/2015 when the instrument was taken out of service? Purpose: T

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Stephen Biss

Apr 5, 2018
2 min

ABA Sequences v ACA Sequences

Purpose: To explain to the Court, the differences between ABA (Esc Esc B) and ACA (Esc Esc C) sequences To confirm that ABA sequences are not recorded in COBRA data but ACA sequences are recorded in COBRA data. To explain to the Court why the calibration checks at 40 or 50, 100, and 300 during annual inspections do not appear in COBRA data disclosed. Sample cross-examination of Crown expert to clarify ABA (and ACABA) sequences v. ACA sequences for the Court: Q. Just, before w

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Why Does the ATC Say Single Point Control Tests are Good Enough?

Stephen Biss

Mar 25, 2018
6 min

Why Does the ATC Say Single Point Control Tests are Good Enough?

Purpose: To explore the differences between a measurement instrument that has a linear relationship between the thing measured and the result v. a measuring instrument that has a calibration curve. To search for an admission that the calibration curve can shift up or down, left or right, or rotate around a point over time. To cross-examine the CFS expert on the lack of empirical study supporting the ATC/CFS hypothesis that a single point control test can always detect drift.

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Stephen Biss

Mar 23, 2018
3 min

Response Drifts Over Time

In an article relied upon by the SCC in St. Onge, Brian Hodgson stated: Defence lawyers need to educate themselves about the meanings of "drift" and "over time". What is it that actually "drifts"? What happens "over time". Are these concepts important to clarify during any cross-examination of a Crown expert? Can the reality of drift over time be satisfied by single point control tests? Is more required to maintain reliability over time? The ATC and CFS regularly opine that a

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Traceability of Measurement Result on an Approved Instrument

Stephen Biss

Feb 14, 2018
4 min

Traceability of Measurement Result on an Approved Instrument

Purpose: To obtain an admission from the CFS scientist that the traceability of a measurement result on an approved instrument or a truck weigh scale is through the calibration of the instrument at the factory or a proper recent re-calibration by the manufacturer or factory authorized service centre. At the time of calibration a calibration curve is created to establish a relationship between the electrical signal coming off the detector in the AI or the weigh scale and the d

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Stephen Biss

Jan 25, 2018
1 min

Police don't follow their Standard Operating Procedures

Purpose: To establish non-compliance with the Standard Operating Procedure respecting entering accurate data into the tombstone data prior to a configuration of the alcohol standard or a subject test To establish improper use of the Esc Esc E function checking date and time To establish bad practice in recording or amending location data in the instrument To establish the unreliability of some of the information on the Intoxilyzer Test Record notwithstanding Criminal Code sec

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Control Tests do not displace Formal Calibration Intervals

Stephen Biss

Jan 13, 2018
7 min

Control Tests do not displace Formal Calibration Intervals

Purpose: To separate conceptually control tests from calibration To obtain an admission that there are no "assessors" in the province of Ontario To obtain an admission that the historical maintenance records show a deterioration of performance - deterioration of linearity in this particular instrument The strategy of using control tests as indication of reliability depends upon completeness of records and transparency To obtain an admission that at the bottom of the valley in

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Beer-Lambert Law as Stated in Training Aid is Over-Simplified and Inadequate

Stephen Biss

Jan 10, 2018
10 min

Beer-Lambert Law as Stated in Training Aid is Over-Simplified and Inadequate

This blog entry contains excerpts from the cross-examination of a CFS scientist during an over 80 trial. It was suggested to the scientist that light in the Intoxilyzer sample chamber is polychromatic, rather than monochromatic. The Beer-Lambert Law as described in the CFS Training Aid assumes that the infrared light in the sample chamber is monochromatic, i.e. that there is one constant co-efficient for ethyl alcohol. Because the infrared infrared light in the sample chambe

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The "known" is the original calibration of the instrument

Stephen Biss

Jan 10, 2018
2 min

The "known" is the original calibration of the instrument

Purpose: To separate the concepts of "calibration" from "control checks" To clarify that "calibration" is something that happens at the factory, not at time of use by a qualified technician To clarify that control tests at time of testing are simply a verification (to use the CFS scientist's words) that calibration hasn't changed over time (note Hodgson concept of "over time" in his paper referred to in St-Onge) Sample Cross-examination on clarification by CFS expert as to wh

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