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Case 1:20-cr-00330-PAE Document 424 Filed 11/08/21 Page6of41 As to Dr. Rocchio’s opinions, Dr. Dietz offers the following responsive opinions: 99 66s e The word “grooming” “imputes motive and intent without adequate evidence of either,” including to the defendant. (Ex. A at 3). e “[G]rooming has no consistent definition, and concerns have been raised that there is no valid method to assess whether grooming has occurred or is occurring.” (/d. at 4 (citation and internal quotation marks omitted)). e “In any particular population of alleged victims, patients, or plaintiffs—including those whom Dr. Rocchio has treated or evaluated—the determination of whether grooming has occurred is a subjective judgment hinging largely on the credibility of individuals. Such judgments have no known error rate and cannot be tested, verified, or reproduced.” e “There is no generally accepted theory of grooming by third parties,” and it is not accepted in the relevant community. “[I]t has not and cannot be tested; and there is no known or potential rate of error.” e The notion that “individuals with particular vulnerabilities are often targeted by perpetrators of sexual abuse” is ‘“‘a commonly accepted bit of clinical lore” that is “not based on empirical data.” As explained below, the Government agrees that Dr. Dietz may offer an opinion on the difficulty of accurately determining whether an act constitutes grooming, in response to Dr. Rocchio. Although his remaining opinions purport to respond to Dr. Rocchio, however, they are themselves unreliable or invade the province of the jury, and should be precluded. Beyond his response to Dr. Rocchio’s opinions, Dr. Dietz offers several additional opinions, to which the Government objects as discussed herein. As to “hindsight bias,” Dr. Dietz opines: e Hindsight bias, or “the tendency to overestimate how predictable or foreseeable an event is after being informed about the outcome of an event,” exists and has been found in various experiments. (Ex. A at 4-5). e Hindsight bias “affects legal judgments.” (dd. at 5). DOJ-OGR-00006217