Hoang v. Vicentini, 2016 ONCA 723

Court of Appeal speaks to the Difference between Litigation Experts & Participant Experts (and the exception to complying with Rule 53.03)

Released October 5, 2016 | Full Decision [CanLII]

The Plaintiff Christopher Hoang was six years old when he was injured in an auto accident. His father (Can Hoang) dropped him and three other children off at an intersection before parking his car.  Christopher was hit by Mr. Vicentini in the intersection. He brought an action against his father and Mr. Vicentini.  After a lengthy trial, the jury found Mr. Can Hoang completely at fault.  The Plaintiff was ordered to pay costs to Vicenti and Mr. Can Hoang was ordered to pay costs to the Plaintiff.

The Plaintiff appealed, asking for a new trial against Vicentini and for an increase to future care costs. The appellant Plaintiff advanced six main grounds of appeal:

  • Did the trial judge err in holding that the police’s automotive service technician was required to comply with r. 53.03 in order to give opinion evidence?
  • Did the trial judge err in admitting opinion evidence from the Police Accident Reconstruction Specialist Detective?
  • Did the trial judge err in her charge by referencing that the brakes operated properly?
  • Did the trial judge err in admitting a human factors expert to give opinion evidence on the “ultimate issue”?
  • Was Hoang’s appointed defence counsel in a conflict of interest?
  • Did the trial judge err in awarding costs?
    • The separate costs awarded to Ford Credit
    • The denial of a Sanderson Order
    • The liability of The Personal to pay costs


With respect to the first question, Justice Brown held the police’s service technician was a participant expert, as described by the Court of Appeal in Westerhof v. Gee Estate, 2015 ONCA 206.  These experts have special skills, knowledge or experience and may give evidence without complying with r. 53.03 when:

  1. The opinion is given is based on the witness’ observation of or participation in the events at issue and
  2. The witness formed the opinion as part of the ordinary exercise of his skill or knowledge while observing or participating in events.

It was noted that the exception afforded to participation experts is based on the fact that disclosure problems do not generally exist.  However, where the opinion of a participant expert is disclosed on the eve of trial the judge has the discretion to exclude the evidence.

In addition to the issue described above, please review the full decision for commentary regarding admissibility of human factors evidence, the importance of making objections at trial (ie. not leaving objections to be heard the first time on appeal), whether a reservation of rights by an insurer amounts to a conflict of interest and the applicability of a Sanderson order. The appeal was dismissed regarding liability and damages but granted on amounts ordered payable to the minor appellant.

Read the full decision on CanLII
Jan Marin
Written by

Jan received her Bachelor of Arts (Honors) in Development Studies from Huron University College at the University of Western Ontario in 2005 and her J.D. from Western's Law School in 2009. While attending law school, Jan volunteered with the school's Community Legal Clinic and Pro-Bono Students Canada. She also participated in an international exchange program at ESADE in Barcelona where she studied both International and European Union law.

Before joining Gluckstein Personal Injury Lawyers, Jan completed her articles at a prominent personal injury firm. She was called to the bar in June 2010.

Jan's personal injury practice is focused on motor vehicle collisions, occupier's liability, product liability and medical malpractice.

When not practicing law, Jan enjoys travelling, playing soccer and volleyball.