Hot-tubbing and pretrial meetings between damages experts

Feb 17, 2020
Financial management Financial consulting Law firms

The case of Tahir v. Mitoff 2019 ONSC 7298 involved the death of a 47-year-old mother and wife as a consequence of alleged medical malpractice. Prior to her death, she worked on a full-time basis as a registered nurse. Although the case was dismissed and no damages were awarded, Justice Darla A. Wilson concluded that the quantum of the financial dependency claim should have been resolved before trial, leaving only the liability and causation issues to be determined at trial.


Items in dispute which, according to the judge, could or should have been resolved prior to trial commencement, included:

Retirement age: The plaintiff’s expert suggested a retirement age of 65, given that retirement ages have been increasing over time. The defence expert considered retirement ages of 60, 63 and 65. The judge held that the deceased would likely have retired at age 63, the average retirement age of public sector workers, given that her husband was 10 years older and would likely have been retired by this time, her pre-existing health issues, and her entitlement to an actuarially unreduced pension.

Age at which children would cease being dependent: The court found that the children’s dependency would likely end at age 25, after completion of university. On this issue, the plaintiff’s expert assumed that the children would be dependent until age 28, while the defence expert assumed dependency until age 22.

Value of employer-paid employee benefits: The value of employer-paid fringe benefits, including drug, dental, extended health and pension benefits, were held to be equal to 11.8 per cent of salary based on a study. The plaintiff’s counsel calculated the value of these benefits at 15.3 per cent, while the defence expert calculated benefits at 11.3 per cent.

Allowance for remarriage: Irrespective of the statistical likelihood of remarriage, there was no evidence that the surviving spouse was contemplating remarriage. For this reason, the defendants’ arguments that an allowance for remarriage was appropriate were not accepted.

Surviving spouse’s income: Notwithstanding reported earnings of approximately $6,000 per annum, the judge held that that the surviving spouse likely earned or was capable of earning $20,000 per annum, based on employment at minimum wage rates. For this reason, his income-earning capacity was valued at $20,000 per annum.

Discount rate: Based on the evidence, which presumably included the age of the deceased and earnings as a registered nurse at the top of her unionized wage scale, Justice Wilson held that there should be no reduction to the Rule 53.09 discount rate for productivity increases (i.e., when income increases in real terms above the rate of inflation). The plaintiff’s expert reduced the discount rate to account for productivity.

Loss of household services: The self-reporting survey completed by the deceased’s family was criticized as being excessive for someone who worked full-time and enjoyed socializing. The judge determined the loss of familial household services at an average of 20 hours per week, based on Statistics Canada data, less an allowance for services personal to the deceased and a replacement cost of $16.50 per hour.

Management fee: The judge held that the onus is on the plaintiff to demonstrate the need for an investment management fee and rejected the claim due to lack of evidence. Management fees are generally awarded only in cases in which the persons receiving the funds do not have the ability to appropriately manage those funds.


In this case, the judge noted that the experts agreed on the general approach but disagreed on the issues outlined above. According to the judge, the experts should have met before trial in an attempt to resolve or narrow the gap in their dependency loss calculations. If, after that, differences of opinion remained, then counsel could have asked for the assistance of the court, possibly with the experts “hot-tubbing.”

Hot-tubbing is a practice that allows the experts to testify in court together on a panel, allowing the experts to challenge each other. This practice is common in Australia where the term was coined, as well as in administrative tribunals in Ontario related to the National Energy Board and the Ontario Municipal Board. Further, pretrial hot-tub-like meetings have been increasing since recent changes to Ontario’s Rules of Civil Procedure.

A meeting between damages experts prior to trial could reduce the number of issues in dispute and may even facilitate the preparation of a spreadsheet that would allow the trier of fact to input decisions on unresolved issues and prepare calculations under alternative scenarios, without the need for opposing experts to testify.

Currently, in Canada, judges may only enforce the use of hot-tubbing in court under the new Federal Courts Rules and the federal Competition Tribunal Rules.


In her closing comments, Justice Wilson quoted from Best Practices for Medical Malpractice Cases, published by the Holland Access to Justice in Medical Malpractice Group, as follows: “In an ideal world, damages would be settled before any trial and counsel should work towards this result. Where damages cannot be settled in their entirety, however, counsel should agree on those heads of damages that can be settled and eliminate those issues. No trial should proceed with all damages issues as live issues.”

The above-noted comments are presumably not restricted to medical malpractice cases; hopefully, it will become more common for plaintiff and defence damages quantification experts to meet (off the record) before trial. While experts may not agree on every issue, they should at a minimum be able to narrow the issues in dispute, and summarize the specific material issues on which they disagree and their impact on damages.

The additional advantages of pretrial meetings between opposing damages quantification experts include reductions in time expended by witnesses in the witness box, court time and the costs associated therewith. In addition, such meetings will likely contribute to fairness by reducing the risks associated with non-experts trying to figure out which expert is correct.

RSM contributors

  • Stephanie Greenwald
    Income Partner

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