In the recent decision Amalathasan v. Certas Home and Auto Insurance Company, 2023 ONLAT 21-006393/AABS, the Licence Appeal Tribunal gave us some guidance on how they intend to apply the doctrine of res judicata to Minor Injury Guideline disputes.  The Applicant was involved in a motor vehicle accident on March 22, 2016. She had previously applied to the LAT in 2020 for a determination regarding whether she qualified for benefits outside of the MIG and for non-earner benefits. The Tribunal released a decision on March 2, 2020 denying the Applicant all benefits.  She subsequently submitted two treatment plans for chiropractic treatment and a chronic pain assessment, which the Respondent denied and the Applicant again submitted an application to the LAT.  In the current Application, the insurer raised the issue of whether res judicata applied given that the LAT had already determined that the Applicant’s injuries fell within the MIG. Adjudicator Jessica Cavdar agreed with the Respondent that the four criteria for a finding of res judicata were met and the Applicant was not entitled to relitigate the MIG.


  1. The parties were the same in both applications;
  2. The prior claim (the 2020 decision) is within the Tribunal’s jurisdiction;
  3. The 2020 decision was on the merits;
  4. And the 2020 decision was a final judgment. Notably, the applicant chose not to seek reconsideration, appeal, or judicial review of the 2020 decision.

However, Adjudicator Cavdar did note that the Applicant could have been successful with this claim if there was evidence that following the release of the 2020 decision her condition worsened such that she no longer belonged in the MIG. For example, if she developed a psychological condition or chronic pain with functional impairments that manifested between the final day of the 2020 Decision’s oral hearing and the present. Unfortunately for the Applicant in this case, no such evidence existed. However, the comments by the LAT do leave open the door for Applicants to bring forward this type of evidence in the future. Therefore, Applicants may not be totally shut out from relitigating the MIG despite the doctrine of res judicata, if they can show that there is new evidence to consider.

Ashley Shmukler is the author of this blog and member of the LAT practice group. If you have a question about this decision or have an issue on a similar file, please contact Ashley at 647-427-3363