R. v. D.D., 2000 SCC 43, [2000] 2 SCR 275

R. v. D.D., [2000] 2 S.C.R. 275

Her Majesty The Queen                                                                   Appellant

v.

D.D.                                                                                                    Respondent

Indexed as:  R. v. D.D.

Neutral citation:  2000 SCC 43.

File No.:  27013.

2000:  March 14; 2000:  October 5.

Present:  McLachlin C.J. and L’Heureux‑Dubé, Gonthier, Iacobucci, Major, Binnie and Arbour JJ.

on appeal from the court of appeal for ontario

Criminal law -- Evidence -- Admissibility -- Expert evidence -- General approach to necessity requirement -- Young child complaining about alleged sexual assaults 30 months after incidents -- Defence counsel indicating that lengthy delay in reporting incidents suggested that complainant had fabricated story -- Child psychologist testifying that length of time before disclosure was not indicative of truth of allegation because many factors and circumstances may affect timing of complaint -- Whether trial judge erred in admitting expert evidence -- Whether necessity requirement met -- Whether principle concerning timing of complaint should be set out in trial judge’s instructions to jury instead of in expert evidence.

The complainant alleged that the accused had sexually assaulted her when she was 5 to 6 years old. The complainant told no one about these events for two and a half years.  At trial, defence counsel cross‑examined the complainant,  who was 10 years old at the time, on the lengthy delay in reporting the incidents and suggested that she had fabricated the story.  The Crown called a child psychologist to testify that a child’s delay in alleging sexual abuse does not support an inference of falsehood.  During a voir dire, the psychologist gave a general explanation applicable to all children that delayed disclosure could occur for a variety of reasons and does not indicate the truth of an allegation.  The trial judge admitted the expert evidence and the jury found the accused guilty of sexual assault and invitation to sexual touching. The Court of Appeal held that the expert evidence should not have been admitted because it was neither relevant nor necessary, set aside the verdict  for this and other reasons, and ordered a new trial.  The Crown appealed from the finding that the expert evidence was inadmissible but agrees that the order for a new trial was warranted based on the Court of Appeal’s other reasons for setting aside the verdict.  On the only issue raised in this appeal, the Court of Appeal held that the expert evidence should not have been admitted.

Held (McLachlin C.J. and L’Heureux‑Dubé and Gonthier JJ. dissenting on the merits):  The appeal should be dismissed.

Per Iacobucci, Major, Binnie and Arbour JJ.:  The psychologist’s evidence was not necessary and should not have been admitted at trial.  The necessity requirement of the Mohan analysis exists to ensure that the dangers associated with expert evidence are not lightly tolerated. While some degree of deference is owed to the trial judge’s discretionary determination of whether the Mohan requirements have been met on the facts of a particular case, that discretion cannot be used to dilute the requirement for necessity.  Mere helpfulness or a finding that the evidence might reasonably assist the jury is not enough to admit an expert’s opinion.  The need for expert evidence must be assessed in light of its potential to distort the fact‑finding process.  Expert opinion is admissible if exceptional issues require special knowledge outside the experience of the trier of fact.  The admissibility requirements governing expert evidence do not eliminate the dangers associated with opinion evidence.  In particular, the province of the jury might be usurped by that of the expert witness and jurors might attorn to the opinion of an expert.  Furthermore, expert opinions usually are derived from unsworn material not available for cross‑examination.  Finally, expert evidence is time‑consuming and expensive.

Here, one statement of principle emerges from the expert evidence: the timing of disclosure signifies nothing; not all children immediately disclose sexual abuse; and the timing of disclosure depends upon the circumstances of the particular victim.  The content of this evidence had no technical quality sufficient to require an expert’s testimony.  It was neither unique nor scientifically puzzling but was rather the proper subject for a simple jury instruction. The doctrine of recent complaint in sexual assault cases as a principle of law no longer exists in Canada and a failure to make a timely complaint must not be the subject of an adverse inference based upon rejected stereotypical assumptions of how persons react to sexual abuse. A trial judge should instruct a jury that there is no inviolable rule on how people who are the victims of trauma like a sexual assault will behave.  In assessing the credibility of a complainant, the timing of the complaint is simply one circumstance to consider in the factual mosaic of a particular case.  A delay in disclosure, standing alone, will never give rise to an adverse inference against the credibility of the complainant. A proper jury charge in this case would have dispelled the possibility of stereotypical reasoning, saved time and expense, and eliminated superfluous or prejudicial content.

Per McLachlin C.J. and L’Heureux‑Dubé and Gonthier JJ. (dissenting on the merits):  The psychologist’s evidence was admissible because it met the test for admitting expert evidence set out in Mohan that requires relevance, necessity, the lack of any other exclusionary rule and a properly qualified expert.  Its probative value also outweighed its prejudicial effects. These criteria are case‑specific and factual.  An appellate court cannot lay down broad rules that categories of expert evidence are always admissible or inadmissible and there is no general rule on the admissibility of expert opinion evidence on delays by children in reporting sexual assault.

The trial judge was correct in finding that the psychologist’s evidence was relevant to a fact in issue at the trial.  The trial turned on the credibility of the complainant and the issue of delay was subsidiary to the complainant’s credibility.  The “fact in issue” was whether a child’s delay in reporting sexual abuse suggests that the alleged abuse did not occur.  This fact was put in issue by the defence indicating that it would ask the jury to infer that the alleged events were fabrications based on the complainant’s delayed reporting of the incident. Whether the complainant was not credible because she delayed disclosure was a fact in issue and the psychologist’s discussion of reasons other than fabrication for a child delaying reporting sexual abuse was relevant to that issue.  Further, it is not a persuasive argument that it is common sense inference rather than a fact that a child’s delay in reporting suggests that the event did not occur.  Issues of fact include both facts and logical inferences that may be drawn from facts.  Moreover, the evidence did not violate the rule against oath‑helping because the psychologist did not interview the complainant and did not testify on whether she had told the truth.  The evidence did implicate the complainant’s credibility but this was permissible and almost inevitable in a case that turns on credibility.

With respect to the necessity requirement, the psychologist’s evidence provided information likely to be outside the ordinary experience and knowledge of the jury and more than merely helpful.  There is still a need to explain children’s reactions to abuse and it was open to the trial judge to conclude that the psychologist’s evidence would assist the jurors by giving them an understanding of the issue of delay in reporting that their ordinary knowledge and experience might not provide.  There is no need to depart from the flexibility of the Mohan approach by adumbrating the necessity requirement with sub‑rules relating to the type of science at issue or with a rule that expert evidence is only needed to explain abnormal behaviour.   Furthermore, the fact that the complainant testified did not preclude the psychologist’s evidence.  The defence put the reasons for delay in question and it was open to the trial judge to permit the Crown to respond with evidence of other possible explanations for the delay.  Lastly, while the need for expert evidence may be diminished if the same objective can be met with a warning to the jury, a warning in this case would not have been a complete substitute for the psychologist’s evidence.  Expert evidence may serve purposes that instruction does not.

Cases Cited

By Major J.

Applied:  R. v. Mohan, [1994] 2 S.C.R. 9; referred to:  R. v. Abbey, [1982] 2 S.C.R. 24; R. v. Dietrich (1970), 1 C.C.C. (2d) 49; R. v. Lillyman, [1896] 2 Q.B. 167; Kribs v. The Queen, [1960] S.C.R. 400; Timm v. The Queen, [1981] 2 S.C.R. 315; R. v. W. (R.), [1992] 2 S.C.R. 122; R. v. M. (P.S.) (1992), 77 C.C.C. (3d) 402; R. v. T.E.M. (1996), 187 A.R. 273.

By McLachlin C.J. (dissenting on the merits)

R. v. Mohan, [1994] 2 S.C.R. 9; R. v. Marquard, [1993] 4 S.C.R. 223; R. v. Morin, [1988] 2 S.C.R. 345; R. v. F. (D.S.) (1999), 43 O.R. (3d) 609; R. v. B. (C.R.), [1990] 1 S.C.R. 717; R. v. K. (A.) (1999), 45 O.R. (3d) 641; R. v. Villamar, [1999] O.J. No. 1923 (QL); R. v. C. (G.) (1996), 110 C.C.C. (3d) 233; R. v. Béland, [1987] 2 S.C.R. 398; R. v. B. (F.F.), [1993] 1 S.C.R. 697; R. v. Burns, [1994] 1 S.C.R. 656; R. v. Lavallee, [1990] 1 S.C.R. 852; R. v. Abbey, [1982] 2 S.C.R. 24; Kelliher (Village of) v. Smith, [1931] S.C.R. 672; R. v. Mair (1998), 122 C.C.C. (3d) 563; R. v. T. (D.B.) (1994), 89 C.C.C. (3d) 466; R. v. C. (R.A.) (1990), 57 C.C.C. (3d) 522; R. v. T.E.M. (1996), 187 A.R. 273; R. v. Ménard, [1998] 2 S.C.R. 109.

Statutes and Regulations Cited

Criminal Code , R.S.C., 1985, c. C‑46 , s. 275  [rep. & sub. c. 19 (3rd Supp.), s. 11].

Authors Cited

Federal/Provincial Task Force on Uniform Rules of Evidence.  Report of the Federal/Provincial Task Force on Uniform Rules of Evidence.  Toronto:  Carswell, 1982.

Learned Hand.  “Historical and Practical Considerations Regarding Expert Testimony” (1901), 15 Harv. L. Rev. 40.

Ontario.  Commission on Proceedings Involving Guy Paul Morin.  The Commission on Proceedings Involving Guy Paul Morin (Kaufman Report).  Toronto:  Ontario Ministry of the Attorney General, 1998.

Paciocco, David.  Expert Evidence:  Where Are We Now?  Where Are We Going?.  Institute of Continuing Legal Education, Canadian Bar Association (Ontario), January 31, 1998.

Paciocco, David M., and Lee Stuesser.  The Law of Evidence, 2nd ed.  Toronto:  Irwin Law, 1999.

Sopinka, John, Sidney N. Lederman, and Alan W. Bryant.  The Law of Evidence in Canada, 2nd ed.  Toronto:  Butterworths, 1999.

Wigmore, John Henry.  Evidence in Trials at Common Law, vol. III, 2nd ed.  Boston:  Little, Brown & Co., 1923.

APPEAL from a judgment of the Ontario Court of Appeal (1998), 113 O.A.C. 179, 129 C.C.C. (3d) 506, 21 C.R. (5th) 124, [1998] O.J. No. 4053 (QL), allowing the accused’s appeal from his conviction for sexual assault and invitation to sexual touching and ordering a new trial.  Appeal dismissed, McLachlin C.J. and L’Heureux‑Dubé and Gonthier JJ. dissenting on the merits.

M. David Lepofsky and Christopher Webb, for the appellant.

P. Andras Schreck, for the respondent.

The reasons of McLachlin C.J. and L’Heureux-Dubé and Gonthier JJ. were delivered by

1                        The Chief Justice  (dissenting on the merits)  --  This case raises the issue of when expert evidence may be admitted regarding a child’s delay in making an allegation of sexual abuse.  The accused in this case says that such evidence is irrelevant, unnecessary and calculated to distort the trial process.  The  prosecution, on the other hand, maintains that the evidence is relevant and necessary.  The trial judge admitted the expert evidence and the jury convicted the accused.  The  Court of Appeal set aside the verdict on other grounds and ordered a new trial.  It also held that the trial judge erred in admitting the expert evidence and that it should not be admitted at the new trial.

2                        The Crown did not appeal the order for a new trial.  The only issue before us is whether the Court of Appeal erred in holding that expert evidence on delay in reporting child abuse should not have been admitted in this case.  The issue is important.  Quite often children do not complain about an alleged sexual assault until some time after the incident.  This raises the question of whether expert evidence is admissible on the issue of what inferences may be drawn from a child’s delay in reporting.

I.  Facts

3                        The prosecution’s case is that the accused, who was living with the complainant’s mother, sexually assaulted the complainant by making her touch his penis on numerous occasions in 1991 and 1992 when she was 5 to 6 years old.  The complainant told no one about these events for two and a half years.  In January 1995, the complainant had a conversation with a school friend about “gross” things, some of which were true and some of which were false.  During the conversation, the complainant told her friend about the assaults.  The friend reported the complainant’s disclosure to a teacher, and the matter was referred to the Children’s Aid Society.  A Society worker interviewed the complainant in the presence of a police officer.  The complainant first said that she could not remember any sexual touching, but later revealed incidents involving the accused.  The accused categorically denies the allegations.

4                        Charges were laid and the matter proceeded to trial.  At the time of the trial the complainant was 10 years old.  Defence counsel cross-examined the complainant on why she had waited so long to report the incidents and suggested that she had fabricated the story to “one up” the stories told by her friend.  In response, the Crown sought to call child psychologist Dr. Peter Marshall to rebut defence counsel’s submission that the lateness of the complainant’s disclosure supported an inference that she was not telling the truth when she said that the accused had sexually assaulted her. The trial judge called a voir dire on the admissibility of Dr. Marshall’s evidence on this point.

5                        During the voir dire, Dr. Marshall discussed delayed disclosure of child sexual abuse, based on his knowledge of the scientific literature in the area.  He testified that there are many factors which can affect the timing of a complaint, including the relationship between the child and the abuser and the nature of the abuse.  Some factors might discourage children from reporting abuse, such as embarrassment; fear of getting themselves or others into trouble; bribery or threats by the perpetrator; fear of being punished or sent away; disruption of the family; or fear that they would not be believed.  Young children might also not fully comprehend what happened or not see anything wrong with the abuse.

6                        Dr. Marshall also discussed the timing of allegations of abuse and its relevance to determining whether the abuse actually occurred.  In his opinion, most sexual abuse is never disclosed, so one cannot assume that disclosure normally happens immediately.  He testified that children disclose at various lengths of time after the event, so there is a continuum from immediate disclosure to delayed disclosure to no disclosure.  When cross-examined by defence counsel as to whether the profile of a victim of abuse could be developed by reference to the timing of the complaint, Dr. Marshall stated “the fact of the delay . . . doesn’t even enter into my thinking as to whether or not it happened....   [T]he research says that the length of time before a child reveals something is not diagnostic”.  The trial judge asked him to clarify what it means when delay is “not diagnostic”, to which Dr. Marshall responded  “[i]t proves nothing either way”.

7                        After Dr. Marshall testified, the trial judge asked defence counsel whether he took issue with Dr. Marshall’s opinion that a delay in disclosure is not diagnostic.  Defence counsel initially agreed that “the delay is provable of nothing”.  Crown counsel sought confirmation of that point, because “the whole tenor of [defence counsel’s] cross-examination of the complainant . . . was, If it happened you would have told somebody”.  Defence counsel then stated that he intended to indicate to the jury that “the fact that the victim did not tell anybody is certainly evidence that it didn’t happen to her”.

II.  Decisions

8                        At the conclusion of the voir dire, the trial judge ruled Dr. Marshall’s evidence admissible. He considered the four criteria for admission of expert evidence set out in R. v. Mohan, [1994] 2 S.C.R. 9:  relevance, necessity, absence of an exclusionary rule and a qualified expert.  He held that the evidence was relevant to the delay in disclosure, given the defence’s position that the jury could draw a “common sense” inference from the delay that the complainant had fabricated the sexual assaults.  On necessity, the trial judge took the view that he was bound by the statement in R. v. Marquard, [1993] 4 S.C.R. 223, at p. 249 (per McLachlin J.), that

[e]xpert evidence has been properly led to explain the reasons why young victims of sexual abuse often do not complain immediately.  Such evidence is helpful; indeed it may be essential to a just verdict.

He also held that Dr. Marshall’s evidence was outside the knowledge and expertise of the jury and that its admission would be necessary for the jury to reach a just verdict.  He found the third and fourth Mohan criteria clearly met as well.  Therefore, he found the expert evidence admissible.

9                        The Court of Appeal ((1998), 113 O.A.C. 179) held that Dr. Marshall’s evidence was neither relevant nor necessary.  To be relevant, evidence must be directed to establishing a fact in issue.  Here the evidence was relevant to the complainant’s credibility, not to a fact in issue.  Nor was the evidence necessary, since it dealt with a matter within the knowledge and experience of the ordinary juror.  Moreover, taking relevance and necessity together, the prejudicial effects of the evidence outweighed its probative value.  For these reasons, the Court of Appeal held that the trial judge had erred in admitting the expert evidence, and directed that it not be admitted at the new trial.

III.  Issue

10                      The key issue on this appeal is whether the Court of Appeal was correct in concluding that Dr. Marshall’s evidence could not meet the criteria of relevance and necessity and hence should not be recalled at the new trial. 

IV.  Analysis

11                      The test for the admissibility of expert evidence was consolidated in Mohan, supra.  Four criteria must be met by a party which seeks to introduce expert evidence:  relevance, necessity, the lack of any other exclusionary rule, and a properly qualified expert.  Even where these requirements are met, the evidence may be rejected if its prejudicial effect on the conduct of the trial outweighs its probative value.

12                      The application of the four Mohan criteria is case-specific.  Determinations of relevance and necessity, as well as the assessment of whether the prejudicial effect of the evidence outweighs its probative value, must be made within the  factual context of the trial.  As Sopinka J. said of relevance in R. v. Morin, [1988] 2 S.C.R. 345, at p. 370, the inquiry “is very much a function of the other evidence and issues in a case”.  Taking into account the other evidence, the issues and her knowledge of the jury, the trial judge determines what are the live issues in the trial and whether the evidence will be necessary to enable the jury to dispose of them.  The point was well put in R. v. F. (D.S.) (1999), 43 O.R. (3d) 609 (C.A.), at p. 625: 

The trial judge has the advantage of hearing the evidence in issue, observing the jury and being able to appreciate the dynamics of the particular trial.... [T]he trial judge may also be in a better position to determine what may come within the normal experience of the average juror in the community in which the case is being tried. 

Finally, the trial judge may be in the best position to determine whether the probative value of the evidence is outweighed by its prejudicial effect on the trial.  The trial judge knows the issues, the evidence and the jury and is charged with the ultimate responsibility of running a fair trial. 

13                      For these reasons appellate courts owe deference to decisions of trial judges to admit or reject expert evidence:  F. (D.S.), supra; R. v. B. (C.R.), [1990] 1 S.C.R. 717.  See also R. v. K. (A.) (1999), 45 O.R. (3d) 641 (C.A.); R. v. Villamar, [1999] O.J. No. 1923 (QL) (C.A.), and R. v. C. (G.) (1996), 110 C.C.C. (3d) 233 (Nfld. C.A.).  This does not preclude appellate review.  Where the record clearly does not support a finding of admissibility on the basis of the Mohan criteria, the Court of Appeal may rule that the evidence should not have been admitted.  However, the case-specific nature of the inquiry means that an appellate court cannot lay down in advance broad rules that particular categories of expert evidence are always inadmissible.  Such a categorical approach would undermine Mohan’s requirement of a case-by-case analysis of the four applicable criteria. 

14                      It follows that we cannot say as a general rule that expert evidence on a child’s delay in reporting sexual assault is always admissible.  Nor can we say it is never admissible.  We can only say that it may be admissible if the four Mohan criteria are satisfied and if the prejudicial impact of the evidence does not outweigh its probative value.  The trial judge erred if he took the comments in Marquard, supra, as indicating as a matter of stare decisis that expert evidence on delayed disclosure always meets the necessity test.  By the same token, it would be erroneous to say that such evidence can never be admitted, as the Crown submits the Court of Appeal suggested.  Admissibility of expert evidence must be determined on a case-by-case basis in the factual context of the case as it develops.

15                      Against this background, I turn to the issue of whether the Mohan criteria for admissibility were met in this case.  

A.  Relevance

16                      The trial judge found Dr. Marshall’s evidence relevant to a fact in issue -- the significance of the child’s delay in reporting.  The Court of Appeal, by contrast, held that the evidence was not relevant to a fact in issue, but only to the complainant’s credibility.

17                      In my view, the trial judge was correct in finding that Dr. Marshall’s evidence was relevant to a fact in issue at the trial.  The trial turned on the credibility of the complainant.  If her testimony was believed, the offence was proved as charged.  If there was a reasonable doubt about her credibility, the case was not made out.  The  issue of delay was subsidiary to the complainant’s credibility.  The “fact in issue” was whether a child’s delay in reporting sexual abuse suggests that the alleged abuse did not occur.  The defence put that fact in issue by indicating that it would ask the jury to infer from the delay in reporting that the alleged events were not real occurrences but fabrications.  According to the defence, the complainant “was not credible because she waited too long”.  That was the fact in issue.  Dr. Marshall’s evidence was relevant to that issue because he discussed reasons other than fabrication, such as fear of not being believed, that might explain why a child would delay reporting sexual abuse. 

18                      It is argued that the relevance requirement is not met because the “fact  in issue” –  that a child’s delay in reporting suggests the events did not occur  –  is not a fact but a common sense inference.  This argument is not persuasive.  How the inference is made does not affect whether there is an issue of fact at stake.  Issues of fact include both facts and the logical inferences which may (or may not) be drawn therefrom.  At trial, defence counsel made an issue of the reason for the delayed allegation, cross-examining the child and asking the jury to infer from the delay that the events did not occur.  For the purposes of determining relevance, it does not matter whether the inference is made by counsel, drawing on “common sense”, or with the assistance of expert evidence.  Either way, what is at issue is a factual proposition put by the defence -- namely, that a child’s delay in reporting abuse makes it more likely that the abuse did not occur.

19                      The Court of Appeal reasoned that Dr. Marshall’s evidence should be excluded because it represented “a blatant attempt to bolster the credibility of the only witness the Crown had to the alleged assault” (para. 18).  Finlayson J.A. noted the principle, with which I agree, that the actual credibility of a particular witness is not generally the proper subject of opinion evidence: see R. v. Béland, [1987] 2 S.C.R. 398; Marquard, supra; R. v. B. (F.F.), [1993] 1 S.C.R. 697; Mohan, supra; R. v. Burns, [1994] 1 S.C.R. 656.  This is known as the rule against oath-helping.  In my view, Dr. Marshall’s evidence did not violate that principle.  In Marquard, supra, at p. 249, I noted that

there is a growing consensus that while expert evidence on the ultimate credibility of a witness is not admissible, expert evidence on human conduct and the psychological and physical factors which may lead to certain behaviour relevant to credibility, is admissible, provided the testimony goes beyond the ordinary experience of the trier of fact.

(See also D. M. Paciocco and L. Stuesser, The Law of Evidence (2nd ed. 1999), at pp. 131-32.)  As Finlayson J.A. recognized, Dr. Marshall had not interviewed the complainant.  He could not and did not testify on the issue of whether she was telling the truth.  That remained for the jury to evaluate, taking into account the testimony given by the child, her mother and Dr. Marshall, along with defence counsel’s argument that the jury should infer fabrication.

20                      As with much evidence in a trial, Dr. Marshall’s testimony could be said to implicate the credibility of the complainant.  Such consequences are permissible and indeed almost inevitable in a case that turns on credibility.  Expert evidence would not be relevant if it did not make one version of events more probable than another, so it almost always affects the believability of one or more witnesses.  It follows that an issue of fact can almost always be reformulated in terms of credibility.  This does not necessarily preclude admitting the expert evidence.  Provided the evidence does not directly address the issue of credibility simpliciter, it may be found relevant, even where the expert’s testimony may increase or diminish the credibility of a witness.  Here the question at trial was whether the respondent sexually assaulted the complainant.  A sub-issue was whether the complainant’s delay in reporting suggested that he did not assault her.  The expert evidence of Dr. Marshall on the reasons why children may delay reporting sexual abuse was relevant to that sub-issue, without being directed at simply bolstering the complainant’s credibility.

B.  Necessity

21                      When it comes to necessity, the question is whether the expert will provide information which is likely to be outside the ordinary experience and knowledge of the trier of fact:  Burns, supra; Mohan, supra; R. v. Lavallee, [1990] 1 S.C.R. 852; R. v. Abbey, [1982] 2 S.C.R. 24; Kelliher (Village of) v. Smith, [1931] S.C.R. 672.  “Necessity” means that the evidence must be  more than merely “helpful”, but necessity need not be judged “by too strict a standard”: Mohan, supra, at p. 23.  Absolute necessity is not required. 

22                      The trial judge concluded that the evidence of delayed disclosure was outside the knowledge and expertise of the jury, citing the statement in Marquard, supra, that such evidence has been properly received in the past.  (As mentioned earlier, if the trial judge was bypassing a thorough examination of necessity on the basis that it could be inferred as a matter of law, he proceeded contrary to the case-by-case method Mohan prescribes.  However, the question before us is whether his conclusion was justified, not how he arrived at it.)  By contrast, the Court of Appeal held that the question of what inferences could be drawn from delay in disclosure was a matter within the knowledge and expertise of the jury, on which they required no expert help.

23                      The issue again may be put in simple terms: was there a sufficient basis for the trial judge to conclude that the issue of the child’s delay in disclosure might involve matters beyond the ordinary knowledge and expertise of the jury?  Was the evidence necessary to enable the trier of fact to properly dispose of the credibility issue?  In answering this question, we must bear in mind that the trial judge is in the best position of determining the level of the jurors’ understanding and what may assist them. 

24                      In my view, there was an ample foundation for the trial judge’s conclusion that Dr. Marshall’s evidence went beyond the ordinary knowledge and expertise of the jury.  Based on his knowledge of the relevant scientific literature, Dr. Marshall was able to present insights into why a child might not report incidents of sexual abuse promptly.  Those insights might not be within the knowledge of the ordinary juror.  Appellate courts have upheld numerous decisions in which trial judges have admitted expert evidence on delayed disclosure to assist the trier of fact in child sexual abuse cases: see, e.g., C. (G.), supra; R. v. Mair (1998), 122 C.C.C. (3d) 563 (Ont. C.A.); R. v. T. (D.B.) (1994), 89 C.C.C. (3d) 466 (Ont. C.A.); R. v. C. (R.A.) (1990), 57 C.C.C. (3d) 522 (B.C.C.A.).  These decisions indicate that there is still a significant perceived need for explanation of children’s reactions to abuse, as it may be outside the knowledge and experience of ordinary people.

25                      Dr. Marshall testified, in essence, that contrary to what the ordinary juror might assume, there is no “normal” child response.  Some abused children complain immediately, others wait for a period of time, and some never disclose the abuse.  Thus the timing of the complaint, he testified, does not help to diagnose whether it is true or fabricated.  He also outlined the factors that may lead to delay in disclosure, such as fear of reprisal, lack of understanding, fear of disrupting the family, the nature of the child’s relationship with the abuser, and the nature of the abuse.  Some of these explanations might have occurred to ordinary jurors as a matter of experience and common sense, but some might not have been apparent to them without expert assistance.  Having heard on the voir dire what Dr. Marshall proposed to say, it was open to the trial judge to conclude that his evidence would assist the jurors by giving them an understanding of the issue of delay in reporting that their ordinary knowledge and experience might not provide.

26                      The accused raises three arguments against the finding that Dr. Marshall’s evidence met the criterion of necessity.  First, he argues that in the area of behavioural science, normal human behaviour should not require expert explanation. Only abnormal behaviour should satisfy the necessity requirement.  Since the factors that  might explain a delay in disclosure -- fear, embarrassment, lack of understanding -- are all normal human reactions and by implication within the ken of the jury, he submits that the necessity requirement is not met.

27                      I am reluctant to depart from the flexibility of the Mohan approach by adumbrating the necessity criterion with sub-rules relating to the type of science at issue.  It seems to me that the wisest course is to retain the present approach.  The trial judge must determine necessity in each individual case judged simply by whether the expert testifies on matters beyond the ordinary juror’s knowledge and experience.  Laying down category-based rules for the admissibility of expert evidence would contradict the principled approach of Mohan.  I see no reason to judge social sciences by a different standard than other sciences.  The Mohan criteria already require a qualified expert and permit scrutiny of the newness or validity of the science on which the proposed evidence is based. 

28                      Moreover, a rule that expert evidence can be called only on abnormal behaviour would raise problems.  It might be difficult to accurately distinguish between “normal” and “abnormal” human behaviour: see Mohan, supra, at pp. 35-36  (thus raising the spectre of ancillary expert evidence on what is normal and abnormal).  Another problem is that the proposed rule rests on a questionable assumption -- that ordinary jurors will invariably know all they need to know about “normal” behaviour in order to do justice in all cases.  Judges and jurors are human, but their knowledge of a particular aspect of human behaviour may not equal that of an expert.  As Wilson J. wrote in Lavallee, supra, at pp. 870-71:

The longstanding recognition that psychiatric or psychological testimony also falls within the realm of expert evidence is predicated on the realization that in some circumstances the average person may not have sufficient knowledge of or experience with human behaviour to draw an appropriate inference from the facts before him or her.

In such cases, expert testimony may be necessary to assist the trier of fact in resolving an issue.  This does not mean, of course, that expert evidence is required in all cases in which the issue of delayed disclosure arises.  It is for the parties to assess, and ultimately the trial judge to decide, whether the facts of a particular case establish a need to put expert evidence before the trier of fact: R. v. T.E.M. (1996), 187 A.R. 273 (C.A.). 

29                      The accused’s second argument against necessity is that the expert evidence on reasons for delay was not required because the child herself explained why she had not reported the incident more promptly.  The fact that the complainant testifies does not preclude the trial judge from admitting other evidence on the issue.  The defence having put the reason for delay in question by suggesting that it showed that the incidents had not occurred, it was open to the trial judge to permit the prosecution to respond with evidence of other possibilities.  In so far as the expert provided information and insights that went beyond the complainant’s testimony and the ordinary juror’s knowledge, it might well have been required to assist the jury in properly assessing her credibility.  Dr. Marshall’s evidence did not simply repeat the complainant’s evidence.  He went further, positing that such explanations are common among child abuse victims.  Furthermore, the current scientific consensus is that the truth or falsity of such an allegation cannot be determined on the basis of its timing.  This was a subject that the child could not and did not attempt to address.

30                      The accused’s third argument on necessity is that to the extent there was something the jury might not know from their own experience, the trial judge could have relayed this instruction to the jury in his charge.  I agree that a trial judge considering the need to call expert evidence can ask whether the same thing could be accomplished by a warning to the jury.  To the extent it can, the need  to call the expert evidence may be diminished.  However, before concluding that a jury direction renders expert evidence unnecessary, the trial judge must be satisfied that the jury instruction will achieve the same purpose as the expert evidence.  If not, the expert evidence may still remain necessary.

31                      In this case, it is suggested that the trial judge could have told the jury that children who suffer sexual abuse do not always complain at the first opportunity and that the jury should not automatically infer from delay in disclosure that the events did not take place and the complainant fabricated them.   It is questionable whether such a warning would have served as a complete substitute for the expert evidence.  The expert testified not only that many children do not report abuse immediately, but also went on to discuss the reasons why children may delay, based on the scientific literature.  This additional information might reasonably have assisted the jury in deciding what, if anything, to infer from the delay, in a way that the proposed direction by the trial judge would not.  If so, the evidence remained necessary.

32                      Moreover, the expert is subject to cross-examination.  After the expert’s evidence is tested by cross-examination, the jury might be in a better position to evaluate the issue of delay than if it only received a simple judicial warning that delay in reporting does not necessarily mean that the child was fabricating the event.  Finally, the trial judge may conclude that the jury needs to receive information on the issue immediately, rather than awaiting the end of the trial.  Given the risks inherent in instructing the jury in segments throughout the trial (see R. v. Ménard, [1998] 2 S.C.R. 109), the trial judge may find expert evidence timely.  In T.E.M., supra, the court  held that a trial judge may instruct the jury that people who suffer sexual abuse do not always complain at the first opportunity and that the trier of fact must not make an adverse inference on the complainant’s credibility based purely on the stereotype that any delay in disclosure indicates falsehood.  The court went on to add that the availability of an instruction does not prevent the parties from also leading expert evidence on the issue.  I agree: expert evidence may serve purposes that instruction does not.

33                      Given the additional assistance that Dr. Marshall’s testimony may have provided to the jury, I cannot conclude that the trial judge erred by failing to find that it was unnecessary because he could have given a jury warning.  This is particularly so in view of the fact that the defence never raised this argument at trial.  That said, the trial judge on the new trial should consider whether the expert’s testimony is necessary to that trial in light of all the relevant circumstances, including the arguments of counsel and the possibility of a judicial instruction.

C.  No Other Exclusionary Rule

34                      The third criterion for admitting expert evidence is that it must not be excluded by the operation of any other rule.  The only exclusionary rule raised here is the principle that an expert may not testify on the ultimate issue of credibility.  As discussed earlier, this rule was not violated because Dr. Marshall testified on an issue that was subsidiary to the complainant’s credibility.  He did not express an opinion on whether her allegations were true or false.  It was left for the jury to determine whether they accepted all, some or none of the evidence of the complainant.

D.  Properly Qualified Expert

35                      The final requirement for admissibility is that the expert be properly qualified.  Neither the accused nor the Court of Appeal suggested that Dr. Marshall was not properly qualified to testify on the subject of delayed disclosure.

E.  Probative Value Versus Prejudicial Effects

36                      This leaves for consideration the general requirement that the probative value of expert evidence must outweigh its prejudicial effects.  Probative value is determined by considering the reliability, materiality and cogency of the expert testimony: see  K. (A.), supra, at para. 114 (per Charron J.A.).  As with the other elements of the Mohan test, probative value and prejudicial effects are case-specific.  The determinations made by the trial judge deserve appellate deference.  In this case,  Dr. Marshall’s evidence brought relevant facts and opinions to the case that were not within the jury’s knowledge and would not otherwise have been available to assist them.  Dr. Marshall’s qualifications were not questioned.  His testimony was understandable and convincing.  Taken together, these factors suggest that the expert evidence possessed considerable probative value.

37                      The accused argues that the probative value of the evidence was outweighed by two important prejudicial effects: (1) that Dr. Marshall’s evidence would neutralize a legitimate line of argument and interfere with his right of self-defence; and (2) that Dr. Marshall’s evidence would distort the trial process through the undue weight the jury may place on expert evidence.

38                      The first alleged prejudicial effect does not withstand scrutiny.  As the trial judge noted in his decision on the voir dire, admitting Dr. Marshall’s evidence would not prohibit defence counsel from making its “common sense” argument that delay casts doubt on whether the alleged assaults occurred.  The Crown’s expert evidence merely countered that argument by providing evidence that it was contrary to the current consensus in the scientific community.  Conflicting evidence and inferences are the natural product of the adversarial nature of the trial process.  Each side seeks to bring evidence to support its arguments.  Expert witnesses are subject to cross-examination to probe the validity of their evidence and the weight to be assigned to it.  At the end of the day, the jury decides what they accept and what they reject.  Evidence is neither inadmissible nor unfair simply because it contradicts an argument put by the other side.

39                      The second prejudicial effect merits closer consideration.  Low value expert testimony can distort the fact-finding process by taking a relatively simple issue, dressing it up in scientific language and presenting the trier of fact with a ready-made decision.  The jury may be tempted to avoid engaging in serious consideration of the actual facts and instead rely on the apparent expertise of the scientist.  In effect, the expert may usurp the domain of the jury.  Trial judges must take this possibility into account in determining whether the prejudicial effect of expert evidence outweighs its probative value.

40                      Part of this concern is addressed at the necessity stage: a party seeking to call expert evidence must show that the subject matter of the expert’s opinion falls outside the likely range of knowledge and experience of the trier of fact.  Nonetheless, that may not suffice.  Even if expert evidence may assist the judge or jury, that benefit must be balanced against its costs. Can the expert address the issue in understandable terms?  Is the judge or jury likely to take the expert’s word as unchallengeable truth, or will the trier of fact be able to examine it critically?  At the same time, the judge must not underestimate the ability of jurors to assess evidence; they may be quite capable of discerning whether scientific information is legitimate or not, as long as it is presented in accessible language.

41                      The concern that the jury may be misled was not made out in this case.  Dr. Marshall testified in a clear and straightforward manner.  He avoided scientific terms which might obfuscate the issue and confuse the jury.  His evidence was easy to understand and well within the ability of the jury to evaluate.  Unlike some expert witnesses, Dr. Marshall did not rely on his credentials or “the mystique of science” to bolster his testimony: see Béland, supra, at p. 434.  Nor did his testimony verge on advocacy.  He neither explicitly nor implicitly commented on the complainant’s credibility or the ultimate issue of the guilt or innocence of the accused.  Defence counsel engaged Dr. Marshall in cross-examination and did not seem hindered by the scientific nature of the evidence.  On the circumstances that prevailed in the trial below,  I cannot conclude that the trial judge erred in holding that the probative value of Dr. Marshall’s evidence outweighed its prejudicial effects.

V.  Conclusion

42                      I conclude that the record amply supports the trial judge’s conclusion that Dr. Marshall’s evidence was admissible.   The Court of Appeal erred in holding that the evidence should not have been admitted and should not be admitted on the new trial.  At the new trial, it will be up to the trial judge to consider the facts, the issues and the submissions of counsel and determine whether the evidence of Dr. Marshall (or any other expert the parties seek to call) meets the Mohan criteria for determining admissibility.

43                      Given that the expert evidence issue was secondary to the Court of Appeal’s main ruling that a new trial is necessary on other grounds, I would dismiss the appeal and confirm the order for a new trial on the issue on which error was conceded.

The judgment of Iacobucci, Major, Binnie and Arbour JJ. was delivered by

44                            Major J. -- This appeal raises the question of whether expert evidence may be admitted to inform the jury that children who have suffered sexual abuse respond in different ways with respect to disclosing the abuse.  The expert here did not interview the child, so his evidence was not specific to this complainant but was a general explanation applicable to all children.

45                            The reasons of the Chief Justice conclude that the evidence of the child psychologist should be admissible as expert evidence.  I reach a different conclusion. In my respectful opinion, the expert evidence tendered by the Crown failed to meet the necessity requirement identified in R. v. Mohan, [1994] 2 S.C.R. 9, to which these reasons are confined.

I.  General Approach to the Necessity Requirement

A.  Standard of Necessity

46                            The second requirement of the Mohan analysis exists to ensure that the dangers associated with expert evidence are not lightly tolerated.  Mere relevance or “helpfulness” is not enough.  The evidence must also be necessary.

47                            I agree with the Chief Justice that some degree of deference is owed to the trial judge’s discretionary determination of whether the Mohan requirements have been met on the facts of a particular case, but that discretion cannot be used erroneously to dilute the requirement of necessity.  Mohan expressly states that mere helpfulness is too low a standard to warrant accepting the dangers inherent in the admission of expert evidence.  A fortiori, a finding that some aspects of the evidence “might reasonably have assisted the jury” is not enough.  As stated by J. Sopinka, S. N. Lederman and A. W. Bryant,

expert evidence must be necessary in order to allow the fact finder: (1) to appreciate the facts due to their technical nature, or; (2) to form a correct judgment on a matter if ordinary persons are unlikely to do so without the assistance of persons with special knowledge. 

(The Law of Evidence in Canada (2nd ed. 1999), at p. 620, citing Mohan, supra, at p. 23.)

B.  Dangers of Expert Evidence

48                            In Mohan, Sopinka J. stated that the need for expert evidence must be assessed in light of its potential to distort the fact-finding process.  A brief examination of the dangers associated with the admission of expert evidence is helpful to the analysis of this appeal.

49                            A basic tenet of our law is that the usual witness may not give opinion evidence, but testify only to facts within his knowledge, observation and experience.  This is a commendable principle since it is the task of the fact finder, whether a jury or judge alone, to decide what secondary inferences are to be drawn from the facts proved.

50                            However, common law courts have since the 14th century recognized that certain exceptional issues require the application of special knowledge lying outside the experience of the usual trier of fact.  Expert opinion evidence became admissible as an exception to the rule against opinion evidence in those cases where it was necessary to provide “a ready-made inference which the judge and jury, due to the technical nature of the facts, are unable to formulate” (R. v. Abbey, [1982] 2 S.C.R. 24, at p. 42).

51                            Despite the emergence of the exception, it has been repeatedly recognized that the admissibility requirements of expert evidence do not eliminate the dangers traditionally associated with it.  Nevertheless, they are tolerated in those exceptional cases where the jury would be unable to reach their own conclusions in the absence of assistance from experts with special knowledge.

52                            Historically, there existed two modes of utilizing such expert knowledge as was available:  first, to select jurors who by experience were best suited to deal with the facts before them, and second, to call experts as friends of the court rather than as witnesses for one side or the other.  (See Learned Hand, “Historical and Practical Considerations Regarding Expert Testimony” (1901), 15 Harv. L. Rev. 40.)  In this manner, the neutrality of the experts was assured.  This notion has long disappeared and now the “professional expert witness” has emerged.  Although not biased in a dishonest sense, these witnesses frequently move from the impartiality generally associated with professionals to advocates in the case.  In some notable instances, it has been recognized that this lack of independence and impartiality can contribute to miscarriages of justice.  (See, e.g., The Commission on Proceedings Involving Guy Paul Morin (Kaufman Report) (1998), at p. 172.)

53                            The primary danger arising from the admission of any opinion evidence is that the province of the jury might be usurped by that of the witness.  This danger is especially prevalent in cases of expert opinion evidence.  Faced with an expert’s impressive credentials and mastery of scientific jargon, jurors are more likely to abdicate their role as fact-finders and simply attorn to the opinion of the expert in their desire to reach a just result.  See Mohan, supra, per Sopinka J. at p. 21:

There is a danger that expert evidence will be misused and will distort the fact-finding process.  Dressed up in scientific language which the jury does not easily understand and submitted through a witness of impressive antecedents, this evidence is apt to be accepted by the jury as being virtually infallible and as having more weight than it deserves.  As La Forest J. stated in R. v. Béland, [1987] 2 S.C.R. 398, at p. 434, with respect to the evidence of the results of a polygraph tendered by the accused, such evidence should not be admitted by reason of “human fallibility in assessing the proper weight to be given to evidence cloaked under the mystique of science”.

54                            The danger of attornment to the opinion of the expert is further increased by the fact that expert evidence is highly resistant to effective cross-examination by counsel who are not experts in that field.  In cases where there is no competing expert evidence, this will have the effect of depriving the jury of an effective framework within which to evaluate the merit of the evidence.

55                            Additional dangers are created by the fact that expert opinions are usually derived from academic literature and out-of-court interviews, which material is unsworn and not available for cross-examination.  Though not properly admissible as evidence for the proof of its contents, this material generally finds its way into the proceedings because “if an expert is permitted to give his opinion, he ought to be permitted to give the circumstances upon which that opinion is based” (R. v. Dietrich (1970), 1 C.C.C. (2d) 49 (Ont. C.A.), at p. 65).  In many cases, this material carries with it prejudicial effects which require special instructions to the jury (Abbey, supra, at p. 45).

56                            Finally, expert evidence is time-consuming and expensive. Modern litigation has introduced a proliferation of expert opinions of questionable value.  The significance of the costs to the parties and the resulting strain upon judicial resources cannot be overstated.  When the door to the admission of expert evidence is opened too widely, a trial has the tendency to degenerate into “a contest of experts with the trier of fact acting as referee in deciding which expert to accept” (Mohan, supra, at p. 24).

C.  Summary of General Approach to Necessity

57                            In summary of the general principles expressed above, I adopt the following passage by Professor Paciocco:

As the Mohan Court explained, the four-part test serves as recognition of the time and expense that is needed to cope with expert evidence.  It exists in appreciation of the distracting and time-consuming thing that expert testimony can become.  It reflects the realization that simple humility and a desire to do what is right can tempt triers of fact to defer to what the expert says.  It even addresses the fact that with expert testimony, lawyers may be hard-pressed to perform effectively their function of probing and testing and challenging evidence because its subject matter will often pull them beyond their competence, let alone their expertise.  This leaves the trier of fact without sufficient information to assess its reliability adequately, increasing the risk that the expert opinion will simply be  attorned to.  When should we place the legal system and the truth at such risk by allowing expert evidence?  Only when lay persons are apt to come to a wrong conclusion without expert assistance, or where access to important information will be lost unless we borrow from the learning of experts.  As Mohan tells us, it is not enough that the expert evidence be helpful before we will be prepared to run these risks.  That sets too low a standard.  It must be necessary.

(D. Paciocco, Expert Evidence:  Where Are We Now?  Where Are We Going? (1998), at pp. 16-17.)

II.  Application of General Principles

A.  Introduction

58                            In my view, the content of the expert evidence admitted in this case was not unique or scientifically puzzling but was rather the proper subject for a simple jury instruction.  This being the case, its admission was not necessary.

59                            Distilling the probative elements of Dr. Marshall’s testimony from its superfluous and prejudicial elements, one bald statement of principle emerges.  In diagnosing cases of child sexual abuse, the timing of the disclosure, standing alone, signifies nothing.  Not all victims of child sexual abuse will disclose the abuse immediately.  It depends upon the circumstances of the particular victim.  I find surprising the suggestion that a Canadian jury or judge alone would be incapable of understanding this simple fact.  I cannot identify any technical quality to this evidence that necessitates expert opinion.

B.  The Law in Relation to Timing of Disclosure

60                            In medieval times, the opinion expressed in Dr. Marshall’s evidence was contrary to our law.  Authorities from as early as the 13th century reveal that the common law once contained an absolute requirement that victims of sexual abuse raise an immediate “hue and cry” in order for their appeal to be heard.  An example is provided by the following archaic passage cited in Wigmore on Evidence (2nd ed. 1923), vol. III, at p. 764:

When therefore a virgin has been so deflowered and overpowered, against the peace of the lord the king, forthwith and while the act is fresh she ought to repair with hue and cry to the neighboring vills and there display to honest men the injury done to her, the blood and her dress stained with blood, and the tearing of her dress; and so she ought to go to the provost of the hundred and to the serjeant of the lord the king and to the coroners and to the viscount and make her appeal at the first county court.

By the end of the 1700s, this formal requirement had evolved into a factual presumption.  See, e.g., Hawkins’ Pleas of the Crown, where the author states:  “It is a strong, but not a conclusive, presumption against a woman that she made no complaint in a reasonable time after the fact” (cited by Hawkins J. in R. v. Lillyman, [1896] 2 Q.B. 167, at pp. 170-71).

61                            Owing to the inflexibility of the common law, the notion of hue and cry persisted throughout most of the 20th century.  See Kribs v. The Queen, [1960] S.C.R. 400, per Fauteux J., at p. 405:

The principle is one of necessity.  It is founded on factual presumptions which, in the normal course of events, naturally attach to the subsequent conduct of the prosecutrix shortly after the occurrence of the alleged acts of violence.  One of these presumptions is that she is expected to complain upon the first reasonable opportunity, and the other, consequential thereto, is that if she fails to do so, her silence may naturally be taken as a virtual self-contradiction of her story.

This reasoning was followed in Timm v. The Queen, [1981] 2 S.C.R. 315.

62                            Today and for some time, the rationale in Kribs has been repeatedly subjected to criticism, is not followed, and has been overruled.  The Report of the Federal/Provincial Task Force on Uniform Rules of Evidence (1982), at p. 301, as cited by Sopinka, Lederman and Bryant, supra, at p. 322, states:

The expectations of medieval England as to the reaction of an innocent victim of a sexual attack are no longer relevant.  A victim may have a genuine complaint but delay making it because of such legitimate concerns as the prospect of embarrassment and humiliation, or the destruction of domestic or personal relationships.  The delay may also be attributable to the youth or lack of knowledge of the complainant or to threats of reprisal from the accused.  In contemporary society, there is no longer a logical connection between the genuineness of a complaint and the promptness with which it is made.

In response to this criticism, Parliament chose to abrogate the authority of Kribs and  Timm by statute (see s. 275  of the Criminal   Code , R.S.C., 1985, c. C-46 ).

63                            Application of the mistake reflected in the early common law now constitutes reversible error.  See R. v. W. (R.), [1992] 2 S.C.R. 122, per McLachlin J. (as she then was) at p. 136:

Finally, the Court of Appeal relied on the fact that neither of the older children was “aware or concerned that anything untoward occurred which is really the best test of the quality of the acts.”  This reference reveals reliance on the stereotypical but suspect view that the victims of sexual aggression are likely to report the acts, a stereotype which found expression in the now discounted doctrine of recent complaint.  In fact, the literature suggests the converse may be true; victims of abuse often in fact do not disclose it, and if they do, it may not be until a substantial length of time has passed.

The significance of the complainant’s failure to make a timely complaint must not be the subject of any presumptive adverse inference based upon now rejected stereotypical assumptions of how persons (particularly children) react to acts of sexual abuse:  R. v. M. (P.S.) (1992), 77 C.C.C. (3d) 402 (Ont. C.A.), at pp. 408-9; R. v. T.E.M. (1996), 187 A.R. 273 (C.A.).

C.  Appropriateness of a Judicial Instruction

64                            Given that the statement of principle expressed by Dr. Marshall reflects the current state of Canadian law, it could have and should have been included in the trial judge’s instructions to the jury.  As this would have effectively dispelled the possibility that the jury might engage in stereotypical reasoning, it was not necessary to inject the dangers of expert evidence into the trial.

65                            A trial judge should recognize and so instruct a jury that there is no inviolable rule on how people who are the victims of trauma like a sexual assault will behave.  Some will make an immediate complaint, some will delay in disclosing the abuse, while some will never disclose the abuse.  Reasons for delay are many and at least include embarrassment, fear, guilt, or a lack of understanding and knowledge.  In assessing the credibility of a complainant, the timing of the complaint is simply one circumstance to consider in the factual mosaic of a particular case.  A delay in disclosure, standing alone, will never give rise to an adverse inference against the credibility of the complainant.

66                            It was submitted that it is preferable to introduce the concept contained in Dr. Marshall’s evidence to the jury by way of expert testimony rather than by judicial instruction.  In my view, this argument is flawed.  There is nothing to be gained from a cross-examination of the simple and irrefutable proposition advanced in this case by the expert.  As well, there is no benefit to be derived from the added flexibility of expert evidence since the undeniable nature of the proposition does not lend itself to future advancements in knowledge and understanding.

67                            A jury instruction, in preference to expert opinion, where practicable, has advantages.  It saves time and expense.  But of greater importance, it is given by an impartial judicial officer, and any risk of superfluous or prejudicial content is eliminated.

68                            In this appeal, the evidence presented by the expert was precisely what the jury would have been instructed by a proper charge.  There is no difference of substance between the two.

III.  Conclusion

69                            The doctrine of recent complaint as a principle of law did not exist in Canada at the time of the trial.  The expert evidence supported the wisdom of having abolished that principle.  There was no basis for the exercise of the trial judge’s discretion to permit expert evidence that supported the correctness of the change in our law.

70                            As a result,  the expert evidence led in this case, as disclosed by the trial record, was not capable and did not meet the second requirement of necessity in the Mohan analysis.  If a proper jury instruction had been given, there was no possibility that the jury would have been unable to grasp the concept because of its technical nature, there being none in this case.  There was no possibility that the jury would reach an erroneous conclusion if not assisted by the expert.

71                            As a consequence, the appeal is dismissed.  I agree with the conclusion of the Ontario Court of Appeal that the expert evidence tendered by the Crown in this case was inadmissible.  As there is to be a new trial in any event, I refrain from deciding whether the prejudicial effect of its admission resulted in a miscarriage of justice on the facts of this case.

Appeal dismissed, McLachlin C.J. and L’Heureux‑Dubé and Gonthier JJ. dissenting on the merits.

Solicitor for the appellant:  The Ministry of the Attorney General, Toronto.

Solicitors for the respondent:  Pinkofsky Lockyer, Toronto.