(905) 415-1636

The Use of Expert Evidence in Court: Rosati v. Reggimenti 2016 ONSC 7013

In this recent Superior Court of Justice decision, the Court undertook a detailed analysis of the use of expert evidence in Court, and to what extent apparent prejudicial or biased evidence should be permitted. The importance of the expert evidence to the core of the matter at hand will have a critical role in determining whether expert evidence should be admitted.

Background

The parties in this case have been involved in multiple courses of litigation and negotiation from their separation in 1995 up to the current matter before the Court. Commencing in 2008 and throughout the course of the litigation thereafter, the wife utilized the services of a forensic accountant for review of the husband’s financial disclosure.

When the forensic accountant was originally engaged, she quoted the wife an estimated fee of $8,000.00 to $16,000.00. By October of 2011, due to the time involved in this specific matter, the fees had reached approximately $70,000.00.

The matter was scheduled for trial in November, 2013. The wife sought to add the forensic accountant as a witness at trial. By this time, her fees were approximately $173,000.00 inclusive of HST. As such, the Court held that she had a financial interest in the matter, as she would not paid for her services unless the wife was successful at trial. Further, the Court found that the accountant had made comments which indicated she may not be unbiased. As such, the accountant was prohibited from giving either expert or factual evidence.

In response, the wife brought a motion requesting the judge recuse herself as the trial judge in the matter. However, the trial judge refused to do so, but did declare a mistrial as her schedule did not permit her to hear the evidence in a timely manner. In addition, the forensic accountant brought a motion to have herself added as an intervenor in the proceedings. However, the accountant eventually withdrew this notice of motion upon receipt of legal advice.

The above noted decision was appealed to the Divisional Court, who ordered the matter returned to be heard before the Regional Senior Justice, and that the hearing of evidence was to be carried on from the point at which the trial had terminated, and that the presiding judge would be bound by prior rulings of the preceding judge, unless he or she determined otherwise.

In February, 2016, the Court heard a motion brought by the wife requesting the Court to reconsider the prior ruling to exclude the forensic accountant’s evidence. The Court found that the wife was able to attempt to requalify the forensic accountant’s evidence, and a voire dire was held on this issue alone.

The forensic accountant testified that at the time she was engaged for services, she did not anticipate the volume of work which was required in this matter. She testified, and the Court was satisfied, that she did not have a contingency arrangement. The forensic accountant further testified that she did not feel she could ethically withdraw her services, as this would be an abandonment of her client.

In November, 2016, the wife entered into a new contract for services with the forensic accountant. The accountant agreed to write off $120,000.00 of her previous services, she would receive $25,000.00 in immediate payment, and $5,000.00 as retainer for participating in the trial.

The wife’s position is that the forensic accountant should be permitted to testify. The husband’s position was that she shouldn’t be permitted to testify, for two reasons. First, she has a vested interest in the outcome, and secondly she was not an unbiased expert, but rather, was an advocate for her client. The husband further claims that the new retainer agreement is a strategic move in an effort to have the forensic accountant’s evidence included.

Analysis

The Court began it’s analysis by referring to the Supreme Court of Canada decision White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23, which established a two-stage test for the qualification of expert evidence. The first stage is the threshold requirements for admissibility; relevance, necessity, and the absence of an exclusionary rule. The second stage provides the judge with discretion to exclude evidence if the prejudice of the evidence outweighs its value. The Supreme Court of Canada held that the issue of impartiality should be initially canvassed at the first stage, within the threshold requirements. However, they can also be considered in the second stage, weighing the value of the evidence against the impartiality of the expert.

The Court found the lack of objectivity to be of greater concern than the new financial arrangements, or any perceived benefit to the forensic accountant thereof. As noted by the Court, financial experts or forensic accountants are commonly retained in family law matters for services such as business and income valuations. A large sum of money being owed to one of the parties does not disqualify an expert. In respect of her impartiality, the Court noted it is not uncommon for an expert to do everything possible to review and compile evidence in preparation of Court. However, experts must remain independent. In this regard, the Court accepted the forensic accountant’s evidence that she brought the motion as an intervenor for the purposes of defending her reputation, and not because of her financial interest in the outcome of the litigation.

The Court then moved on to discuss the relevance of the forensic accountant’s evidence, and found it to be necessary in respect of understanding the financial disclosure which has been produced, and when. The Court acknowledged they would need her evidence with respect to tracing the financial information. However, the Court noted that her opinions in respect of the conduct of the husband, is one to be made by a judge. As such, her opinions regarding the delay, fraud, and intentional non-disclosure is not required. If they become necessary at some point with respect to the course of her investigation, the Court can accept such evidence at that time.

The Court ultimately held that the value of the evidence to be provided by the forensic accountant outweighed its prejudicial impact. As such, her evidence was permitted to the extent that it did not relate to husband’s conduct.

More From the Feldstein Blog

Ontario Family Law, Translated

The statute is dense. The stakes are personal. These articles unpack the parts clients ask about most.

Case Blog

Razavi v. Golzari 2026 ONSC 2686

Background  The parties met in 2013 through mutual family and friends. Around the same time, the husband purchased a home in his sole name. Shortly after the purchase, the wife ... Read more

July 11, 2026 · 8 min read

Feldstein Family Law Group, P.C.

The Law Is Complex.
The First Step Isn't.

Free, confidential consultation with an experienced Ontario family law lawyer. One call can change everything.

Markham · Oakville · Mississauga · Vaughan

Call (905) 415-1636

Responses within one business day — often the same day.

Our Offices

Serving Families Across Ontario & the Greater Toronto Area

Four Feldstein Family Law Group offices across the GTA — close to where our clients live, work, and raise their families.

Markham

20 Crown Steel Dr Suite 8
Markham, ON L3R 9X9, Canada

Map & Directions

Mississauga

3464 Semenyk Ct Suite 213
Mississauga, ON L5C 4P8, Canada

Map & Directions

Vaughan

3865 Major MacKenzie Dr W Suite 107
Vaughan, ON L4H 4P4, Canada

Map & Directions

Oakville

209 Speers Rd Suite 5
Oakville, ON L6K 0H5, Canada

Map & Directions

Communities We Serve

Feldstein Family Law Group represents clients across the Greater Toronto Area — including Toronto, Markham, Oakville, Mississauga, Vaughan, Richmond Hill, Thornhill, Unionville, Stouffville, Aurora, Newmarket, Brampton, Etobicoke, North York, Scarborough, Burlington, Milton, Georgetown, Woodbridge, Maple, King City, and the surrounding communities of York Region, Peel Region, Halton Region, and Durham Region.