7. The Use of Written Authorities to Examine and Cross-examine the Expert

• Author: David M. Paciocco - Lee Stuesser
• Profession: Justice of the Ontario Court of Justice - Professor of Law, Bond University
• Pages: 214-215

Page 214

Technically, books and articles are hearsay when they are being relied upon as providing accurate information. Although expertise is often garnered by reading the factual claims and opinions of others, this is inherent in the nature of study. The hearsay foundation for expertise is not treated, therefore, as problematic. On the other hand, the rules of evidence do not permit reliance on books and articles in the examination or cross-examination of experts unless certain criteria are met. The expert can refer to and even quote from other authorities while testifying in chief so long as he adopts the opinions contained in those authorities as his own by expressing his agreement with them. In theory, the trier of fact is then being presented with his opinion, and not that of the author.

Page 215

The expert can be cross-examined using texts, articles, and studies, but according to established law, only where she acknowledges that the works being used are authoritative. Where she acknowledges the authority of the work, if she adopts the opinions of the author they become part of her evidence. Where she acknowledges the authority of the work but rejects its conclusions, she can be asked to explain why, and her responses can be of relevance to the credibility of the opinion she offers.¹⁷⁹In R. v. Marquard, the Supreme Court of Canada was asked to modify this rule to allow authorities to be used in cross-examination even if the expert does not recognize their authority, so long as the reliability of the work is established independently or by judicial notice.¹⁸⁰This is the rule used by a number of American courts. Under the Canadian approach, an expert unfamiliar with the authorities in his field cannot be confronted with them. In effect, the ignorance of the expert insulates him from having to explain the inconsistency of his views with the opinions of others. The Marqua...