Background
MB was convicted in 2023 on 11 charges of serious sexual offending against C over approximately three months in 2000, when he was 36 and she was 15. The two met through an internet chatroom. C alleged that MB — whose photograph had depicted a much younger man — picked her up from school, immediately began plying her with substances, and abused her over several days at an apartment and a motel. He also photographed and filmed the conduct and used that material to coerce her continued co-operation. The offending came to light when police tracked C to the apartment after her family reported her missing. C disclosed the alleged offending to a boyfriend in 2000 but did not make a formal report until 2020, explaining that she had seen MB’s online profile referencing camera equipment and feared he would target other young women.
MB gave evidence denying all sexual conduct. He said C had contacted him online because she was struggling at home and threatened self-harm, that he allowed her to stay at an apartment out of a desire to help, and that others including his partner were aware of those efforts. The Crown offered counter-intuitive evidence in the form of an agreed statement of facts under s 9 of the Evidence Act 2006, covering delayed reporting, grooming and normalisation behaviours, coercive control, and reasons why an abused adolescent may not report to a parent. MB appealed his convictions on two grounds: (1) the prosecutor misused the counter-intuitive evidence in cross-examination and closing address, and the trial judge failed to give corrective directions; and (2) the prosecutor impermissibly led repetitive, leading evidence from C after her evidential video had been played. The Court of Appeal dismissed the appeal.
The Supreme Court heard MB’s case together with TW v R [2026] NZSC 77, which raised materially similar issues. Separate judgments were issued in the two matters, with this judgment addressing the overarching principles.
The Court’s Holding
The Supreme Court allowed the appeal, quashed the convictions, and ordered a retrial. The Court found that the prosecutor had used the counter-intuitive evidence in an impermissible, diagnostic manner — arguing in cross-examination of MB and in closing address that C’s behaviour corresponded to behaviours described as typical of abuse victims, and that MB’s behaviour corresponded to characteristics described as typical of offenders. This invited the jury to reason that because C’s (and MB’s) conduct matched the patterns described in the evidence, C’s account was therefore more likely to be true. The trial judge neither corrected that misuse nor gave any adequate directions explaining the purpose and limits of counter-intuitive evidence. The combined effect was a material misdirection warranting a new trial.
The Court took the opportunity to comprehensively restate and extend the principles first articulated in DH v R [2015] NZSC 35, setting out thirteen principles (at [12]) governing the admission, use, and judicial direction of counter-intuitive evidence. The core rule is that such evidence is purely educative: it corrects misconceptions that jurors may bring to their assessment of complainant behaviour, but it says nothing about the credibility of the particular complainant and does not make the alleged offending more or less likely to have occurred. The Court specifically rejected the invalid syllogism — “delayed reporting is common among abuse victims; this complainant delayed; therefore abuse occurred” — as logically unsound because the major premise is true only of some, not all, members of the class.
The Court also emphasised that judicial directions are required as a matter of course whenever counter-intuitive evidence is led, not only when a prosecutor has misused it. Juries must be told the evidence is sourced from generic research studies independent of the case, that its compilers did not interview anyone involved, and that it neither proves nor disproves any allegation. At the same time, juries must not be misdirected that a complainant’s relevant behaviours — such as delayed reporting — are irrelevant to credibility; that assessment remains a question of fact for the jury.
Key Takeaways
- Counter-intuitive evidence serves a purely corrective (educative) function: it neutralises potential juror misconceptions about victim behaviour but cannot be used diagnostically to bolster the complainant’s credibility or to suggest the accused fits an offender profile.
- Prosecutors must not link counter-intuitive evidence to the specific complainant’s account in examination or address; it is particularly difficult to justify reference to such evidence when cross-examining the defendant or leading evidence from the complainant.
- Trial judges must always direct the jury on the purpose and limits of counter-intuitive evidence — its generic research basis, its independence from the facts of the case, and the prohibition on diagnostic reasoning — regardless of whether the prosecutor has overtly misused it.
- The jury may still treat relevant complainant behaviours (e.g., delayed reporting) as bearing on credibility; it is a misdirection to tell them that the counter-intuitive evidence renders such behaviours irrelevant.
- Where counter-intuitive evidence includes probabilistic or frequency language, or extends to offender characteristics, the need for careful judicial direction is heightened.
Why It Matters
Delivered alongside its companion TW v R [2026] NZSC 77, this judgment responds to what the Court describes as a systemic problem: counter-intuitive evidence has become standard in New Zealand sexual offending trials (now almost universally presented as agreed statements under s 9 of the Evidence Act), yet prosecutors repeatedly misuse it as substantive proof of guilt and trial judges routinely fail to correct them or give adequate directions. The Court of Appeal had itself been allowing a series of appeals on this basis, yet in both this case and TW it had dismissed the appeals — prompting the Supreme Court to intervene with authoritative guidance. Practitioners and trial judges now have a clear, consolidated statement of thirteen principles to apply.
The decision is significant for defence practitioners in sexual cases as a reminder that diagnostic use of counter-intuitive evidence is reversible error, and for Crown counsel and the judiciary as a clear warning that the problem must be addressed at trial rather than managed on appeal. The Court framed the issue explicitly as one requiring systemic correction to reduce retrials and the associated burden on victims, defendants, and the courts.