Mohan, Assessments & Expert Evidence: Understanding the Family Law Context

Abstract

Despite the frequent involvement of a range of experts in family law cases, controversy persists over the role of expert witnesses in these cases. Judges have a gatekeeping function in deciding whether to order an assessment or admit expert evidence. In making these decisions, judges should be guided by the type of analysis that the Supreme Court developed in R. v. Mohan, but they should take into account the family law context.For child related issues, the court may appoint a mental health professional to conduct an assessment. A court-appointed assessor has a role that differs from that of a party-retained expert. This paper reviews some of the controversy in the literature and jurisprudence about the role of mental professionals in the family court process, and addresses three related but distinct questions that about the role of mental health professionals in custody, access and child welfare cases: • Why, when and how should a court order an assessment? • When should a court admit evidence from a party-retained expert?• How much weight should be placed on the opinion of an assessor or other expert? In family law cases, mental health professionals can provide important information about children and parents that otherwise may be unavailable, and which should be considered in making prospective decisions about the future care of children. Court-appointed assessors have a significant institutional role in the family law context that has no equivalent in the criminal law context; assessors have a role as delegated fact finders, and their recommendations may be very influential with the courts. They also play an important role in facilitating settlements. The decision about whether to appoint an assessor is not governed by Mohan, though courts should weigh the costs and benefits of ordering an assessment. An assessment report that is consistent with the scope of the order is admissible without further qualification of the author. Party-retained experts also have a significant role in family cases, but the admissibility of their evidence is governed by Mohan. Judges and lawyers must be aware of the limitations and costs as well as the value assessors and other experts. While these professionals often play an important role in child-related disputes, inevitably there is a degree of clinical judgement and subjectivity in their evidence, and the assessment process itself can be time-consuming, intrusive and expensive. There are situations in which the courts should not order an assessment or admit testimony from an expert. In appropriate cases, opinions of assessors and experts should be discounted. A common ground for rejecting an expert's recommendation is that the experts made an error in determining the facts of a case.Accountants and valuators retained by the parties to family law cases often have a central role in the resolution of economic issues; the admissibility of this type of evidence is subject to the application of the Mohan test, though even for this issue the cost-benefit weighing should take account of the private nature of the dispute and the type of matters in dispute. The paper discusses jurisprudence from across Canada, but places some emphasis on legislation and caselaw from Ontario.