The admissibility and persuasiveness of expert evidence

Parenting plan evaluators are expert witnesses who offer their opinion. Courts in common law jurisdictions generally do not accept evidence of an opinion as it is not considered to be reliable evidence from which to establish a fact. An exception to that general principle is expert opinion evidence. In short, an opinion from a person with specialized knowledge or expertise about the area in which they are an expert may be sufficiently reliable to form an evidentiary basis from which to make a finding of fact, provided the opinion meets certain criteria. These criteria will be discussed in this article, as well as what is relevant, reliable and persuasive evidence. The relevant legal principles will be examined in an historical and contemporary, theoretical and practical context. The authors reflect on their considerable experience as consumers of expert evidence and apply this to parenting plan evaluations, as well as considering future challenges in the field.