New Results Require New Evidence: the Application of Res Judicata in the Context of LAT Hearings

November 05, 2026

By Laura Bruce

The Divisional Court’s recent decision in Muddapati v. Primmum Insurance Company, 2026 ONSC 1878 provides clarity on the doctrine of res judicata in the accident benefits context.

Background

The Appellant was involved in a motor vehicle accident on May 2, 2020. She applied for accident benefits and appealed several denials that were based on the MIG limits to the Licence Appeals Tribunal. After a hearing on her first Application, the Tribunal held that the MIG applied and the benefits were properly denied. The Appellant’s request for reconsideration of this first Application was also denied.

The Appellant then brought a second Application (Muddapati v. Primmum Insurance Company, 2025 ONLAT 25- 004140/AABS-PI) after two additional treatment plans were denied, and the matter proceeded to a preliminary issues hearing.

The Appellant argued that the Respondent had failed to take several important steps:

  1. It failed to remove her from the MIG after learning that she had sustained an injury that was not subject to the MIG limits;
  2. It failed to provide the adjusters’ log notes until more than a year and a half after the written hearing in the first Application; and
  3. It failed to consider new evidence in the form of an IE psychiatric assessment report which diagnosed her with Somatic Symptom Disorder, Chronic.

Accordingly, res judicata did not apply, and she should be removed from the MIG limits and have access to the treatment plans in dispute.

In support of her argument, the Appellant cited the Supreme Court of Canada decision Toronto (City) v. CUPE Local 79, 2003 SCC 63, which sets out the factors to be considered in waiving res judicata:

  1. The first proceeding was tainted by fraud or dishonesty;
  2. Fresh, new, evidence is submitted that was previously unavailable that would conclusively impeach the original results; or
  3. When fairness dictates that the original result should not be binding in the new context.

The Appellant relied on the last two grounds, as well as a procedural argument that the Respondent had failed to comply with s.38(9) of the SABS by failing to give her notice in the denial letters that her injuries fell within the MIG limits. She argued that the Respondent was statue-barred from taking the position that the MIG applied by virtue of s.38(11)(1).

The Respondent argued that the defence of res judicata was applicable as the Tribunal had already determined that the Appellant was subject to the MIG limits. The Applicant had been informed by letter dated September 27, 2021 that her injuries fell within the MIG limits. The Appellant’s failure to request the log notes was not equivalent to them not existing and, in any case, they did not contain any evidence that would call the denials into question. The references to the Appellant being outside of the MIG limits were based on erroneous information that the Appellant had fractured her leg and, once the error came to light, the Respondent had informed the Appellant in writing that her injuries fell within the MIG.

The Tribunal agreed with the Respondent. It held that the IE assessor, Dr. Ahmed Jwely, based his report on the Appellant’s self-reporting on various psychometric tests, the Appellant’s medical records (which were unchanged from the time of the decision in her first Application), the OCF-18 in question and the Respondent’s partial approval letter. He did not comment on the applicability of the MIG, only on the unapproved portion of the treatment plan in dispute.

It further held that the adjuster’s log notes were available at the time of the Appellant’s first hearing and her failure to request them did not make them unavailable. The Tribunal commented that, even if the Appellant had requested the log notes, the notes themselves were not medical evidence. The contents of the notes also did not factually support her claim that the Respondent knew she had sustained injuries outside the MIG, as they supported the Respondent’s argument that it had initially been told that the Appellant had suffered a fracture and payments beyond the MIG limits had been made before medical records were received that indicated no such injury.

As it had determined that res judicata applied, there was no need to consider the procedural arguments involving s.38.

The Application was dismissed, as was her request for reconsideration, and so the Appellant then sought judicial review of this Tribunal decisions.

Issue

Did the Tribunal err in finding that res judicata applied and in applying s. 38(9) of the SABS?

Analysis

The Appellant argued that the Tribunal had misapprehended the facts and that res judicata should not apply. She argued that s.38(9) of the SABS requires insurers to notify claimants if they believe that the MIG limits apply and that s.38(11) operates as a bar reliance on the MIG for insurers who fail to give such notice. She also argued that new evidence had, in fact, been introduced, in the form of the adjuster’s log notes and Dr. Jwely’s report, which diagnosed her with Somatic Symptom Disorder and that this diagnosis placed her outside of the MIG limits.

The Test for Res Judicata

The test for res judicata was set out in Danyluk v. Ainsworth Technologies Inc., 2001 SCC 44, [2001] 2 SCR 460 at para. 25. It can be applied where:

  1. The same question has been decided;
  2. The judicial decision which is said to create the estoppel was final; and
  3. The parties to the judicial decision are the same persons as the parties to the proceedings in which the estoppel is raised.

Both parties agreed that the Danyluk test was the correct test to apply, but the Appellant argued that the Tribunal erred in applying it by incorrectly interpreting s. 38(9) and failing to consider the fresh evidence in the adjuster’s log notes and the insurer’s examination report.

Procedural Requirements of the SABS

Subsection 38(9) states that:

38(9) If the insurer believes that the Minor Injury Guideline applies to the insured person’s impairment, the notice under subsection (8) must so advise the insured person.

If an insurer fails to do so, the consequences are set out in s. 38(11):

(11) If the insurer fails to give a notice in accordance with subsection (8) in connection with a treatment and assessment plan, the following rules apply:

1. The insurer is prohibited from taking the position that the insured person has an impairment to which the Minor Injury Guideline applies.

2. The insurer shall pay for all goods, services, assessments and examinations described in the treatment and assessment plan that relate to the period starting on the 11th business day after the day the insurer received the application and ending on the day the insurer gives a notice described in subsection (8).

Standard of Review

Both parties also agreed that the standard of review is correctness as per Canada (Minister of Citizenship and Immigration) v. Vavilov, 2019 SCC 65, at para. 37.

Outcome

The Court was unconvinced by the Appellant’s argument that the Respondent’s failure to cite the MIG in the denials at issue in the second Application triggered s. 38(11), holding that the Respondent had complied with s. 38(9) in both a letter dated September 27, 2021 in which it advised the Appellant that it believed her injuries fell within the MIG. Since the Appellant had failed to provide the respondent with compelling medical evidence warranting her removal from the MIG, s.38(11) was not engaged.

As for the fresh evidence, the Court held that the Tribunal was correct in determining that the adjuster’s log notes could have been obtained in time for the original hearing and that they did not impeach the findings at the original hearing. The Court also held that the Tribunal was correct in finding that the medical examiner had reached a new diagnosis but not on the basis of any new, previously unavailable medical evidence.

Take Aways

Claimants will not be permitted to rely on old evidence to reach new conclusions. New evidence must come in the form of medical records and not the claimant’s self-reporting.

Res judicata will apply to claims advanced at the LAT where treatment plans have already been denied, unless and until new, compelling medical evidence suggests otherwise.  That new evidence must come in the form of medical records, as a claimant’s self-reporting is insufficient in and of itself.