Following the passage of the Evidence Amendment Act, which imposed limits on the number of expert reports that can be tendered for evidence in motor vehicle accident claims, there has been limited judicial treatment.
Section 12.1(2) of the Evidence Act imposes a limit of three experts per vehicle injury proceeding. Parties seeking to introduce additional experts must do so by way of consent, by way of application, by jointly retaining experts, or the court may make orders for their own experts.
In the case of Cooper v. Clements, 2022 BCSC 1775, Justice Weatherhill framed the issues as being whether pursuant to s.12.1(5) of the Evidence Act the plaintiff should be allowed to serve three experts for each of the three motor vehicle accidents they were involved in, whether an expert could tender more than one report, and whether any of the expert reports are inadmissible or should be excised for violating the Mohan Principles relating to expert evidence.
The plaintiff sought to admit 26 expert reports into evidence.
Justice Weatherhill wrote that to be granted leave for filing additional expert reports, the plaintiff must prove two criteria:
 An application under s.12.1(5) of the Evidence Act for leave to file additional expert reports requires the plaintiff to prove the two criteria in s. 12.1(6): (1) that the subject matter of the additional evidence sought to be tendered is not already addressed by other expert evidence; and (2) that without the additional expert evidence, she would suffer prejudice disproportionate to the benefit of not increasing the complexity and cost of the proceeding: Vespaziani v. Lau, 2021 BCSC 1224 at para. 29.
 The first condition of s. 12.1(6) seeks to root out duplication or “piling on” of expert reports. The question is not so much whether there is overlap amongst some of the reports, but whether the specific subject matter of the proposed additional reports is already addressed in other reports tendered by the plaintiff. The fact that each author may possess specific expertise in different disciplines is a relevant consideration: Raniga v. Kang, 2021 BCSC 2340 para. 15.
 The second condition of s. 12.1(6) is a weighing exercise to balance the prejudice to the party of not having the benefit of the expert report against the impact of the expert report on the cost and complexity of the case: Raniga at para. 24.
In sum, in order for additional experts to be admitted, the opinions must be on a necessary subject matter where there is no other expert evidence available, and where the balance between prejudice and proportionality weighs in favour of allowing additional experts.
Justice Weatherhill went on to rule that 11 of the 26 expert reports were inadmissible, five reports from a single expert should be consolidated into one report, and it was open to the defendants to object to passages of many of the reports that were admitted.
Interestingly, we note a potentially fruitful body of case law that could inform disputes around expert reports or specialties of experts that does not appear to have been squarely put before the courts when interpreting the new expert evidence legislation.
Pursuant to Rule 7-2(6) of the Supreme Court Civil Rules, a court “may order a further [independent medical] examination under this rule.” This provision has traditionally been used as a tool of the defence when seeking additional expert evidence when plaintiff counsel have not consented to further examinations.
The recent case of Anderson v. Steffen, 2021 BCSC 252 revisited this issue. There, the test to meet for additional IMEs was summarized as whether there is a question that could not have been answered during the previous medical examination. By analogy, the burden to meet for additional experts in s.12.1(5) applications may be usefully framed as question of whether the previous experts were unable or unqualified to provide opinions on issues that were in play during the litigation, as discussed in Rule 7-2(6) jurisprudence.
As is the case when similar considerations apply for applications to oppose amendments and strike pleadings (in both cases, whether the pleadings, if presumed to be true, are doomed to fail), it may be useful to encourage the courts to consider the analogy to be drawn between s.12.1 of the Evidence Act and Rule 7-2(6).