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In this case, the court was confronted with several issues pertaining to making changes to a final custody order, however, the interesting legal issue looked at the issue of whether professional witnesses should be admissible in unilateral custody assessments.


The father and mother were both seeking to change a joint custody order related to their child that stipulated that the parties have joint custody of their 6 year old son, with parallel decision-making responsibilities. Prior to the trial, the mother had alleged to health professionals and CAS on multiple occasions that the father was sexually and physically abusing the child. The court found that she either raised unfounded allegations against the father or her stated concerns and fears were irrational. She went out of her way to portray the father in a negative light to almost every professional involved in the child’s care. She had been previously found in contempt for interfering with the father’s access. The mother sought to introduce evidence from a psychologist and psychiatrist to support her position. Ultimately, Justice Sherr excluded all of the psychologist’s evidence and the psychiatrist's evidence was limited to determining whether the mother had any psychiatric issues that would impact her parenting capacity. The court did not admit other opinions in the psychiatrist's report.


In rejecting the evidence, the court summarized the role of the judge as gate keeper with respect to admitting expert evidence, and reviewed all of the leading cases. In particular, there is a detailed review of the important 2015 Supreme Court of Canada case on this issue, White Burgess Langille Inman v. Abbott and Haliburton Co. Justice Sherr excluded the evidence due in large part to its unreliability. He noted that at the core of the admissibility analysis is the reliability of the proposed evidence, and that unreliable evidence should never be necessary or relevant. He explained the importance of considering reliability at the gatekeeper stage as it will not be worth the time and cost involved to introduce unreliable evidence.

After taking into consideration that the psychologist never saw the child prior to providing an opinion, the court excluded her evidence because it was "so seriously flawed that it did not even meet the standard of threshold reliability." Furthermore, the court found that it was not relevant, necessary, objective or fair; and it was one sided and unbalanced. Justice Sherr went on to point out the very serious flaws in the psychologist's evidence. Justice Sherr made many of the same findings with respect to the psychiatrist’s evidence and found serious flaws in his report and methodology leading to the conclusion that large portions of his evidence were unreliable and inadmissible. Justice Sherr found that he had insufficient information to give an opinion about whether the child was in any emotional danger from the mother who unilaterally retained the psychiatrist and paid for his report. The court held that the psychiatrist’s evidence did not pass the first stage of the White Burgess test and would not have passed the second stage of the White Burgess test – the gatekeeper step. The unreliability of his evidence, combined with its unfairness and lack of objectivity dictated that its prejudicial effects outweighed its probative value.

In his conclusion, Justice Sherr commented that this decision should provide a message of caution to family law assessment professionals before they accept a unilateral request to provide expert evidence in custody disputes. He stated that this decision should also provide a clear message that assessors not only need to contain their opinions to their fields of expertise, but that they should not give opinions on matters where they have inadequate information to provide reliable opinions. He warned that most courts will likely treat such reports with great caution. This comprehensive decision about expert evidence and unilateral custody assessments should provide some guidance to assessors and counsel as to what information and methodology will be required by the court before such evidence is found to be admissible.