Cornell University Law School Social Science and Law

Witness Reliability in Sexual Assault Cases: Dr. Barbara Ziv Testimony in the Cosby Case

Compiled by Jennifer Mancini, Makiko Ono, and Anna Russell

Bio: Dr. Ziv is a trained forensic psychiatrist who received her M.D. from Northwestern MedicalSchool. She is on the Medical-Legal Advisory Board for the Prevention of Child Abuse and the Pennsylvania Sex Offender Assessment Board. Additionally, she teaches at Temple University Medical School, is the Medical Director at Aetna, has her own private practice, and has testified in 190 cases around the country before the Cosby case in 2018.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1525122

The Social Science Research Background: In this case, Dr. Ziv testified for the prosecution about behavioral patterns of individuals who are involved in sex crimes. She submitted a 17 page report compiling information based on evaluating and treating hundreds of individuals and cited many peer reviewed articles. She testified to knowledge that is well accepted in the forensic psychiatry community, but there is little discussion during her testimony about the methodology behind the claims she is making. The Pennsylvania Statute controlling admissibility in this case only allowed her to testify about general information, and she could not make any comments on the victim’s credibility. In fact, she testified that she knew very little about this case before her testimony and that she has no personal interest in the outcome of the case.

Testimony in the Cosby Case: Dr. Ziv testified that despite people believing that most rape is perpetrated by a stranger, in fact, 85% of rape happens by someone known to the individual. Additionally, only 5-30% of rape gets reported to any authority and, of the small percent that do get reported, there is usually a delay before reporting. Since most rape is perpetrated by an aquaintance, individuals often try to minimize what happened to them after the assault. Survivors have to make sense of it first before they report it and psychologically that takes time. Most adult women victims take on a lot of personal blame and this is exacerbated if they voluntarily consumed alcohol. Most women do not fight back and find themselves “frozen” in time and, in the 85% of cases committed by an acquaintance, most women do not immediately flee the situation. Additionally, survivors rarely confront their abusers, but survivors very commonly go back or sometimes even date or have consensual sexual relations with their abuser. This is an attempt to gain control. When someone is assaulted, regardless of if drugs were involved, their memory is impacted and they likely will not be able to tell a neat chronology of what happened and this could explain inconsistent testimony. It is rare for there to be physical evidence in sexual assault cases so it becomes a he said she said and women fear loss of control of the narrative.

Lastly, people are more likely to place blame on the victim in date rape than a stranger, which is the large majority of cases.

Admissibility:

           The court did not do a Frye hearing, even though PA is a Frye state.  The defense submitted a “Motion In Limine to Exclude or Limit the Expert Testimony of Dr. Barbara Ziv and Dr. Veronique Valliere” or do a Frye hearing, but the court declined to do so. Defendant’s Motion in Limine to Exclude or Limit the Expert Testimony of Dr. Barbara Ziv & Dr. Veronique Valliere, Commonwealth. v. Cosby, Nos. 3932-16, 3314 EDA 2018, 2019 WL 2157653 (Pa. Com. Pl. May 14, 2019) (No. CP-46-CR-3932-2016), 2018 WL 1981819. Instead, the court assessed the admissibility of Dr. Ziv’s testimony by Voir Dire before taking her testimony at trial.  That’s because in PA, the admissibility of expert testimony for criminal cases involving sexual violence is controled by statute 42 Pa. Stat. and Cons. Stat. Ann. § 5920 (West 2012), which states:
           “(b)(1) to be qualified, an expert must have specialized knowledge beyond the average layperson, based on experience/specialized training/education in criminal justice, behavioral sciences or victim services issues related to sexual violence, and that will assist the trier of fact in understanding: the dynamics of sexual violence, victim responses to sexual violence and the impact of sexual violence on victims during and after being assaulted.
           (b)(2) may testify about general victim responses and victim behaviors.
           (b)(3) may NOT testify about the credibility of specific witnesses/victims.” 42 Pa. Stat. and Cons. Stat. Ann. § 5920 (West 2012).
           Dr. Ziv passed this statutory standard for admissibility, and her testimony was admitted.  Interestingly, Dr. Veronique Valliere had given similar expert testimony in the first trial (before a hung jury caused a retrial); but she had crossed the line and given her opinion on facts specific to the case (and made biased public statements), so the prosecution ended up replacing her with Dr. Ziv in the second trial.

Under Frye:
           If the court had done a Frye hearing, Dr. Ziv’s testimony would still probably have been admitted, because it is generally accepted in the field of forensic psychiatry.

Under Daubert:
           If Dr. Ziv’s testimony had been subjected to a Daubert hearing, it is less clear that it would be admissible.  She relied on peer-reviewed sources, but it is unclear what the methodology supporting her statements actually is.  It seems that she did not do any independent research herself for this case, but simply reported, in a “social framework” way, on the general consensus of the field of forensic psychiatry about this topic.  So it’s difficult to assess what “error rate” means in this situation, or whether the methodology is sound.

 

Relevance of Expert Testimony:
Cosby was charged with 3 counts of Aggravated Indecent Assault of Andrea Constand in 2004 pursuant to: 18 Pa. Stat. and Const. Stat. Ann. § § 3125 (a)(1), (a)(4), (a)(5):
           “(a)(1) without the complainant's consent;
           (a)(4) the complainant was unconscious;
           (a)(5) substantially impaired the complainant's power to control his or her conduct by administering, without the complainant’s knowledge, drugs or intoxicants;”  18 Pa. Stat. and Cons. Stat. Ann. § 3125 (West 2003).
Though it was never specified, it seems Dr. Ziv’s testimony largely went to the issue of consent in the first count charged.  The background she gave addressed the kinds of credibility arguments that the prosecution expected the defense to make to discredit Ms. Constand’s testimony:
Defense’s Challenges to Witness Reliability:
The defense challenged Ms. Constand’s general reliability as a witness by highlighting behavior that they alleged contradicted her claim that she had been assaulted.  Some of the facts they highlighted were: Ms. Constand took tea and a muffin from him the morning after the assault; she kept in contact with him afterwards, primarily by phone; she went to dinner with him afterwards and then went to his house alone and confronted him about the assault, in response to which he told her she had orgasmed; she took her mom to a performance by Cosby and interacted with him afterwards; she didn’t report the assault until she spoke to her mom about it 1 year later.  Though Dr. Ziv never addressed any of these specific points, her “social framework” testimony provided context to explain Ms. Constand’s behavior as normal for survivors of sexual violence.  By supporting the general credibility of Ms. Constand as a witness, Dr. Ziv’s testimony also countered 2 other credibility attacks used by the defendant: 1) that Ms. Constand fabricated the allegations to obtain money from the defendant, and 2) that the defendant was not at his home at the time of the alleged assault.
The defense complained of the prejudicial effect of the prosecution’s decision to present Dr. Ziv’s testimony at the very beginning of the trial, before Ms. Constand testified.  This was an unusual choice and may have helped the jury to see Ms. Constand as a more credible witness because they listened to her testimony through the framework of the expert testimony Dr. Ziv had already given.
The jury ended up convicting Mr. Cosby on all 3 counts and ordered a “Sexually Violent Predator Assessment.”  Commonwealth. v Cosby, No. CP-46-CR-3932-2016, 2018 WL 4608704 (Pa. Com. Pl. Sep. 25, 2018).

The Court’s Treatment:
The court of Common Pleas of Montgomery County (O’NEIL Judge, Com. v Cosby, Jr., No. 3314 EDA 2018, 2019 WL 2157653 (Pa.Com.Pl. May 14, 2019) properly allowed the evidence under 42 Pa. C.S.A. § 5920.  But the main issue was whether the court could apply the rule to an offense that occurred 12 years prior to the conception of the statute. This is not about the evaluation of expert testimony, but about the constitutional question to the rule.
The role of the expert: “Dr. Barbara Ziv testified as an expert in understanding the dynamics of sexual violence, victim responses to sexual violence, and the impact of sexual violence on victims during and after being assaulted.” Id., at 42.  Superior Court of Pennsylvania affirmed (Commonwealth v. Cosby, 2019 PA Super 354, 224 A.3d 372 (2019).).  The testimony’s admissibility is not an issue.

Questions:
Because Mr. Cosby had a jury trial and the judge did not write about the evaluation of Dr. Ziv, we do not know the role of the expert exactly. We have some questions and opinions about the treatment.
No Frye test for admissibility:
           1) The defense submitted a “Motion In Limine to Exclude or Limit the Expert Testimony of Dr. Barbara Ziv and Dr. Veronique Valliere” or do a Frye hearing, which the court denied. Is it correct?  (Instead, they assessed the admissibility of Dr. Ziv’s testimony under  PA, the admissibility of expert testimony for criminal cases involving sexual violence is controled by statute 42 PA C.S.A. § 5920.)
Relevance:
           1) Why would Dr. Ziv’s testimony about offender behavior be irrelevant, but testimony about survivor behavior be admissible?  (Offender behavior might not be admissible because this was character evidence (FRE 404).)
           2) Why should survivor behavior be relevant, when that’s not an element of the crime?  (To prove the consent of the victim.)
           3) Why would the testimony of a forensic psychiatrist be relevant to answering these questions?  (By understanding the survivor’s behavior,  the jury can decide whether there was consent of the survivor or not.)
Role of the evidence:
Social context about victim behavior.
           1) Is the victim expert testimony critical for this case?
           a. The victim kept in touch with the defendant and reported the offense to the mother 1 year later. To think about these behaviors and consent, Dr. Ziv’s testimony might be useful for the jury.
           b. At the first trial, the court did not admit the victim expert testimony and the jury reached a deadlock. However, on count one, that is about consent, the jury voted 10-2 to find Cosby guilty. On the third count, that was about using drugs, the jury was also deadlocked at 10-2, in favor of the guilty verdict. On the second count, that was about unconsciousness, the vote was 11-1 to acquit Cosby [see the helpful links]. And in this case, The jury convicted on all 3 counts.
           c. The expert testimony might not be useful for other counts. At least, the defendant did not argue about the disqualification of the expert. Therefore, the expert testimony was important, but only one factor in this case.