Expert opinion evidence
 20.2 (1) In this rule, “joint litigation expert” means a litigation expert engaged to provide expert opinion evidence for two or more parties; (“expert commun du litige”) “litigation expert” means a person engaged for the purposes of litigation to provide expert opinion evidence; (“expert du litige”) “participant expert” means a person who is not engaged to provide expert opinion evidence for the purposes of litigation, but who provides expert opinion evidence based on the exercise of his or her skills, knowledge, training or experience while observing or participating in the events at issue. (“expert participant”) O. Reg. 250/19, s. 8. Expert witness reports (2) A party who wishes to call a litigation expert as a witness at trial shall, at least six days before the settlement conference, serve on all other parties and file a report signed by the expert and containing, at a minimum, the following: 1.  The expert’s name, address and area of expertise. 2.  The expert’s qualifications, including his or her employment and educational experiences in his or her area of expertise. 3.  The nature of the opinion being sought and each issue in the case to which the opinion relates. 4.  The instructions provided to the expert in relation to the case. 5.  The expert’s opinion on each issue and, where there is a range of opinions given, a summary of the range and the reasons for the expert’s own opinion within that range. 6.  The expert’s reasons for his or her opinion, including, i.  a description of the factual assumptions on which the opinion is based, ii.  a description of any research or test conducted by or for the expert, or of any independent observations made by the expert, that led him or her to form the opinion, and, for each test, A.  an explanation of the scientific principles underlying the test and of the meaning of the test results, and B.  a description of any substantial influence a person’s gender, socio-economic status, culture or race had or may have had on the test results or on the expert’s assessment of the test results, and iii.  a description and explanation of every document or other source of information directly relied on by the expert in forming the opinion. 7.  An acknowledgement of expert’s duty (Form 20.2) signed by the expert. O. Reg. 250/19, s. 8. Same, more than one party (3) If two or more parties wish to call a joint litigation expert as a witness at trial, subrule (2) applies with necessary modifications. O. Reg. 250/19, s. 8. Supplementary report (4) Any supplementary report by a litigation expert must be signed by the expert, and shall be served on all other parties and filed, (a)  at least 30 days before the start of the trial; or (b)  in a child protection case, at least 14 days before the start of the trial. O. Reg. 250/19, s. 8. Documents to accompany report (5) The following documents shall accompany a report when it is served on a party under subrule (2), (3) or (4), unless the documents have already been served on the party: 1.  A copy of any written statement of facts on which the litigation expert’s opinion is based. 2.  A copy of any document relied on by the litigation expert in forming his or her opinion. O. Reg. 250/19, s. 8. Restriction on testimony (6) Unless a judge orders otherwise, a litigation expert may not testify about an issue at trial unless the substance of the testimony is set out in a report that meets the requirements of this rule. O. Reg. 250/19, s. 8. Cross-examination (7) A joint litigation expert may be cross-examined at trial by any party. O. Reg. 250/19, s. 8. When joint litigation expert required (8) Litigation expert opinion evidence concerning the following matters may only be presented by a joint litigation expert: 1.  A claim respecting decision-making responsibility, parenting time or contact with respect to a child, unless the court orders otherwise. 2.  Any other matter specified by the court. O. Reg. 250/19, s. 8; O. Reg. 42/21, s. 11. Motion for directions (9) If parties who wish or are required to engage a joint litigation expert do not agree on a matter relating to the engagement, any one of them may make a motion for directions. O. Reg. 250/19, s. 8. Order re joint litigation expert (10) The court may, on motion under subrule (9) or otherwise, make an order engaging a joint litigation expert for two or more parties. O. Reg. 250/19, s. 8. Same (11) In making an order under subrule (10), the court shall ensure that the matters listed in subrule 20.3 (2) are either set out in the order or are otherwise addressed by the order. O. Reg. 250/19, s. 8. Cooperation (12) Parties who engage a joint litigation expert, or for whom a joint litigation expert is engaged, shall cooperate fully with the expert and make full and timely disclosure of all relevant information and documents to the expert, and the court may draw any inference it considers reasonable from a party’s failure to do so. O. Reg. 250/19, s. 8. Restriction on experts on same issue (13) If a joint litigation expert provides opinion evidence on an issue for a party, no other litigation expert may present opinion evidence on that issue for that party, unless the court orders otherwise. O. Reg. 250/19, s. 8. Participant expert (14) A party who wishes to call a participant expert as a witness at trial shall, (a)  at least six days before the settlement conference, (i)  serve notice of the fact on all other parties, and (ii)  if the party wishes to submit any written opinion prepared by the expert as evidence in the trial, serve the written opinion on all other parties and file it; and (b)  serve on any other party, at that party’s request, a copy of any documents supporting the opinion evidence the participant expert plans to provide. O. Reg. 250/19, s. 8. Late filings (14.1) Unless the trial judge or judge managing the case orders otherwise, the time to serve or file a report, opinion or other document under this rule may only be extended under subrule 3 (5) (order to lengthen or shorten time) by an order made at the settlement conference, together with an order with respect to costs. O. Reg. 349/23, s. 4. Application to motions for temporary orders or for summary judgment (15) Unless the court orders otherwise, this rule applies, with the following modifications, to the use of expert opinion evidence on a motion for a temporary order under rule 14 or a motion for summary judgment under rule 16: 1.  Expert witness reports and any supplementary reports shall be served and filed as evidence on the motion in accordance with the requirements of subrules 14 (11), (11.3), (13) and (20), as applicable. 2.  Any other necessary modifications. O. Reg. 250/19, s. 8. RULE 20.3: COURT-APPOINTED EXPERTS Court-appointed experts