The second stage involves the application of the general
exclusionary rule, which assesses whether the benefits of admitting
the evidence outweigh any potential harm its reception occasions
to the trial process.
 At the second stage of the admissibility analysis, it is open
to defence counsel to endeavour to show that the prejudicial effect
of the evidence exceeds its probative value. This analysis focuses on
the DRE’s administration of the evaluation. It may involve
exposing limitations, such as the absence of a standardized
approach to weighing the various tests in reaching a determination
of drug impairment. Or the failure of the DRE to explain how she
drew the inference of drug impairment on the basis of the 12-step
evaluation. Cross-examination of the DRE on the admissibility
inquiry may expose these deficiencies and persuade the trial judge
to exclude the evidence on the basis of the cost benefit analysis.
The relevance of the rolling log
 When Crown counsel tenders as evidence the opinion of
a DRE formed from conducting the 12-step evaluation test, counsel is of necessity asserting that the DRE’s conclusion affords
reliable evidence of drug impairment of an accused’s ability to
operate a motor vehicle. It follows that any evidence that has
a tendency to cast doubt on the reliability of the DRE’s conclusion
is relevant. Evidence of the DRE’s prior experience in conducting
drug recognition evaluations would seem relevant on this basis.
 Apart altogether from the statutory requirements of
s. 657.3(3)(a) of the Criminal Code, disclosure of a proposed expert
witness’ CV has been commonplace. This is because the CV is relevant to the witness’ qualifications to give expert opinion evidence
and the weight to be assigned to any evidence the witness is permitted to give. Indeed, in this case, the DRE’s CV seems to have
been eventually provided. Recall that the CV is a document in
which the IACP requires the DRE to include some of the same
details about evaluations as are recorded in the rolling log.
 This is not a case governed by Jackson or Gubbins. In
those cases, the accused sought disclosure of historical records
relating to the performance of an approved instrument on other
occasions. But the material issue in each case had nothing to do
with the instrument’s performance on other occasions. The material issue in those cases was how the approved instrument worked
when it measured Jackson’s and Gubbins’ blood alcohol levels.
Expert evidence confirmed that the historical data could say
nothing about that. And expert evidence was necessary because
persons of ordinary experience could not establish or negate the
link between past performance and present functionality. That is