907.01   Opinion testimony by lay witnesses.
907.02   Testimony by experts.
907.03   Bases of opinion testimony by experts.
907.04   Opinion on ultimate issue.
907.05   Disclosure of facts or data underlying expert opinion.
907.06   Court appointed experts.
907.07   Reading of report by expert.
Ch. 907 Note NOTE: Extensive comments by the Judicial Council Committee and the Federal Advisory Committee are printed with chs. 901 to 911 in 59 Wis. 2d. The court did not adopt the comments but ordered them printed with the rules for information purposes.
907.01 907.01 Opinion testimony by lay witnesses. If the witness is not testifying as an expert, the witness's testimony in the form of opinions or inferences is limited to those opinions or inferences which are all of the following:
907.01(1) (1)Rationally based on the perception of the witness.
907.01(2) (2)Helpful to a clear understanding of the witness's testimony or the determination of a fact in issue.
907.01(3) (3)Not based on scientific, technical, or other specialized knowledge within the scope of a witness under s. 907.02 (1).
907.01 History History: Sup. Ct. Order, 59 Wis. 2d R1, R205 (1973); 1991 a. 32; 2011 a. 2.
907.01 Annotation When a victim admitted injecting heroin about 72 hours before testifying, the trial court properly denied the defendant's request that the witness display his arm in the presence of the jury in an attempt to prove that the injection was more recent. Edwards v. State, 49 Wis. 2d 105, 181 N.W.2d 383 (1970).
907.01 Annotation An attorney, not qualified as an expert, could testify regarding negotiations in which the attorney was an actor, including expressing opinions about the transaction, but could not testify as to what a reasonably competent attorney would or should do in similar circumstances. Hennig v. Ahearn, 230 Wis. 2d 149, 601 N.W.2d 14 (Ct. App. 1999), 98-2319.
907.01 Annotation Using Lay Opinion Evidence at Trial. Coaty. Wis. Law. May 2009.
907.02 907.02 Testimony by experts.
907.02(1)(1)If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if the testimony is based upon sufficient facts or data, the testimony is the product of reliable principles and methods, and the witness has applied the principles and methods reliably to the facts of the case.
907.02(2) (2)Notwithstanding sub. (1), the testimony of an expert witness may not be admitted if the expert witness is entitled to receive any compensation contingent on the outcome of any claim or case with respect to which the testimony is being offered.
907.02 History History: Sup. Ct. Order, 59 Wis. 2d R1, R206 (1973); 2011 a. 2.
907.02 Annotation A chemist testifying as to the alcohol content of blood may not testify as to the physiological effect that the alcohol would have on the defendant. State v. Bailey, 54 Wis. 2d 679, 196 N.W.2d 664 (1972).
907.02 Annotation The trial court abused its discretion in ordering the defendant to make its expert available for adverse examination because the agreement was for the exchange of expert reports only and did not include adverse examination of the expert retained by the defendant. Blakely v. Waukesha Foundry Co., 65 Wis. 2d 468, 222 N.W.2d 920 (1974).
907.02 Annotation In a personal injury action, the court did not err in permitting a psychologist specializing in behavioral disorders to refute a physician's medical diagnosis when the specialist was a qualified expert. Qualification of an expert is a matter of experience, not licensure. Karl v. Employers Insurance of Wausau, 78 Wis. 2d 284, 254 N.W.2d 255 (1977).
907.02 Annotation The standard of nonmedical, administrative, ministerial, or routine care in a hospital need not be established by expert testimony. Any claim against a hospital based on negligent lack of supervision requires expert testimony. Payne v. Milwaukee Sanitarium Foundation, Inc., 81 Wis. 2d 264, 260 N.W.2d 386 (1977).
907.02 Annotation In the absence of some additional expert testimony to support the loss, a jury may not infer permanent loss of earning capacity from evidence of permanent injury. Koele v. Radue, 81 Wis. 2d 583, 260 N.W.2d 766 (1978).
907.02 Annotation A res ipsa loquitur instruction permits a jury to draw an inference of general negligence from the circumstantial evidence. Before a res ipsa loquitur instruction can be given, the evidence must conform to these requirements: 1) the event in question must be of the kind that does not ordinarily occur in the absence of negligence; and 2) the agency or instrumentality causing the harm must have been within the exclusive control of the defendant. A res ipsa loquitur instruction may be grounded on expert testimony in a medical malpractice case; the res ipsa loquitur standards are satisfied if the testimony and the medical records taken as a whole would support the inference of negligence or if direct testimony is introduced that the injury in question was of the nature that does not ordinarily occur if proper skill and care are exercised. Kelly v. Hartford Casualty Insurance Co., 86 Wis. 2d 129, 271 N.W.2d 676 (1978).
907.02 Annotation A hypothetical question may be based on facts not yet in evidence. Novitzke v. State, 92 Wis. 2d 302, 284 N.W.2d 904 (1979).
907.02 Annotation It was not error to allow psychiatric testimony regarding factors that could influence eye witness identification, but to not allow testimony regrading the application of those factors to the facts of the case. Hampton v. State, 92 Wis. 2d 450, 285 N.W.2d 868 (1979).
907.02 Annotation A psychiatric witness, whose qualifications as an expert were conceded, had no scientific knowledge on which to base an opinion as to the accused's lack of specific intent to kill. State v. Dalton, 98 Wis. 2d 725, 298 N.W.2d 398 (Ct. App. 1980).
907.02 Annotation Medical records as explained to the jury by a medical student were sufficient to support a conviction; the confrontation right was not denied. Hagenkord v. State, 100 Wis. 2d 452, 302 N.W.2d 421 (1981).
907.02 AnnotationPolygraph evidence is inadmissible in any criminal proceeding. State v. Dean, 103 Wis. 2d 228, 307 N.W.2d 628 (1981).
907.02 Annotation Stating guidelines for admission of testimony by hypnotized witnesses. State v. Armstrong, 110 Wis. 2d 555, 329 N.W.2d 386 (1983).
907.02 Annotation No witness, expert or otherwise, should be permitted to give an opinion that another mentally and physically competent witness is telling the truth. State v. Haseltine, 120 Wis. 2d 92, 352 N.W.2d 673 (Ct. App. 1984).
907.02 Annotation Expert testimony regarding fingernail comparisons for identification purposes was admissible. State v. Shaw, 124 Wis. 2d 363, 369 N.W.2d 772 (Ct. App. 1985).
907.02 Annotation Bite mark evidence presented by experts in forensic odontology was admissible. State v. Stinson, 134 Wis. 2d 224, 397 N.W.2d 136 (Ct. App. 1986).
907.02 Annotation An expert may give opinion testimony regarding the consistency of the complainant's behavior with that of victims of the same type of crime only if the testimony will assist the fact-finder in understanding evidence or determining a fact, but the expert is prohibited from testifying about the complainant's truthfulness. State v. Jensen, 147 Wis. 2d 240, 432 N.W.2d 913 (1988).
907.02 Annotation Experience, as well as technical and academic training, is the proper basis for giving expert opinion. State v. Hollingsworth, 160 Wis. 2d 883, 467 N.W.2d 555 (Ct. App. 1991).
907.02 Annotation If the state seeks to introduce testimony of experts who have personally examined a sexual assault victim that the victim's behavior is consistent with other victims, a defendant may request an examination of the victim by its own expert. State v. Maday, 179 Wis. 2d 346, 507 N.W.2d 365 (Ct. App. 1993). See also State v. Schaller, 199 Wis. 2d 23, 544 N.W.2d 247 (Ct. App. 1995), 94-1216.
907.02 Annotation Expert opinion regarding victim recantation in domestic abuse cases is permissible. State v. Bednarz, 179 Wis. 2d 460, 507 N.W.2d 168 (Ct. App. 1993).
907.02 Annotation When the state inferred that a complainant sought psychological treatment as the result of a sexual assault by the defendant, but did not offer the psychological records or opinions of the therapist as evidence, it was not improper for the court to deny the defendant access to the records after determining that the records contained nothing material to the fairness of the trial. State v. Mainiero, 189 Wis. 2d 80, 525 N.W.2d 304 (Ct. App. 1994).
907.02 Annotation An expert may give an opinion about whether a person's behavior and characteristics are consistent with battered woman's syndrome, but may not give an opinion on whether the person had a reasonable belief of being in danger at the time of a particular incident. State v. Richardson, 189 Wis. 2d 418, 525 N.W.2d 378 (Ct. App. 1994).
907.02 Annotation Expert testimony is necessary to establish the point of impact of an automobile accident. Wester v. Bruggink, 190 Wis. 2d 308, 527 N.W.2d 373 (Ct. App. 1994).
907.02 Annotation Scientific evidence is admissible, regardless of underlying scientific principles, if it is relevant, the witness is qualified as an expert, and the evidence will assist the trier of fact. State v. Peters, 192 Wis. 2d 674, 534 N.W.2d 867 (Ct. App. 1995).
907.02 Annotation An indigent may be entitled to have the court compel the attendance of an expert witness. It may be error to deny a request for an expert to testify on the issue of suggestive interview techniques used with a young child witness if there is a “particularized need" for the expert. State v. Kirschbaum, 195 Wis. 2d 11, 535 N.W.2d 462 (Ct. App. 1995), 94-0899.
907.02 Annotation Items related to drug dealing, including gang-related items, is a subject of specialized knowledge and a proper topic for testimony by qualified narcotics officers. State v. Brewer, 195 Wis. 2d 295, 536 N.W.2d 406 (Ct. App. 1995), 94-1477.
907.02 Annotation Generally expert evidence of personality dysfunction is irrelevant to the issue of intent in a criminal trial, although it might be admissible in very limited circumstances. State v. Morgan, 195 Wis. 2d 388, 536 N.W.2d 425 (Ct. App. 1995), 93-2611.
907.02 Annotation As with still photographers, a video photographer's testimony that a videotape accurately portrays what the photographer saw is sufficient foundation for admission of the videotape, and expert testimony is not required. State v. Peterson, 222 Wis. 2d 449, 588 N.W.2d 84 (Ct. App. 1998), 97-3737.
907.02 Annotation It was error to exclude as irrelevant a psychologist's testimony that the defendant did not show any evidence of having a sexual disorder and that absent a sexual disorder a person is unlikely to molest a child because the psychologist could not say that the absence of a sexual disorder made it impossible for the defendant to have committed the alleged act. State v. Richard A.P., 223 Wis. 2d 777, 589 N.W.2d 674 (Ct. App. 1998), 97-2737. See also State v. Davis, 2002 WI 75, 254 Wis. 2d 1, 645 N.W.2d 913, 00-2916.
907.02 Annotation When the issue is whether expert testimony may be admitted, and not whether it is required, a court should normally receive the expert testimony if the requisite conditions have been met and the testimony will assist the trier of fact. State v. Watson, 227 Wis. 2d 167, 595 N.W.2d 403 (1999), 95-1067.
907.02 Annotation A witness's own testimony may limit the witness's qualifications. A witness who disavowed being qualified to testify regarding the safety of a product was disqualified to testify as an expert on the product's safety. Green v. Smith & Nephew AHP, Inc., 2001 WI 109, 245 Wis. 2d 772, 629 N.W.2d 727, 98-2162.
907.02 Annotation If the state is to introduce Jensen, 147 Wis. 2d 240 (1988), evidence through a psychological expert who has become familiar with the complainant through ongoing treatment, or through an intensive interview or examination focused on the alleged sexual assault, the defendant must have the opportunity to show a need to meet that evidence through a psychological expert of its own as required by Maday, 179 Wis. 2d 346 (1993). State v. Rizzo, 2002 WI 20, 250 Wis. 2d 407, 640 N.W.2d 93, 99-3266.
907.02 Annotation A determination of whether the state “retains" an expert for purposes of Maday, 179 Wis. 2d 346 (1993), cannot stand or fall on whether or how it has compensated its expert. An expert's status as the complainant's treating therapist does not preclude that expert from being “retained" by the state for purposes of Maday. State v. Rizzo, 2002 WI 20, 250 Wis. 2d 407, 640 N.W.2d 93, 99-3266.
907.02 Annotation When an expert was permitted to testify in a sexual assault case about common characteristics of sexual assault victims and the consistency of those characteristics with those of the victim at trial, a standing objection to the expert's testifying was insufficient to preserve specific errors resulting from the testimony. State v. Delgado, 2002 WI App 38, 250 Wis. 2d 689, 641 N.W.2d 490, 01-0347.
907.02 Annotation For a defendant to establish a constitutional right to the admissibility of proffered expert testimony, the defendant must satisfy a two-part inquiry determining whether the evidence is clearly central to the defense and the exclusion of the evidence is arbitrary and disproportionate to the purpose of the rule of exclusion, so that exclusion undermines fundamental elements of the defendant's defense. State v. St. George, 2002 WI 50, 252 Wis. 2d 499, 643 N.W.2d 777, 00-2830.
907.02 Annotation Under the first part of the inquiry, a defendant must demonstrate that the proffered testimony satisfies each of the following four requirements: 1) the testimony of the expert witness meets the standards under this section governing the admission of expert testimony; 2) the expert testimony is clearly relevant to a material issue in the case; 3) the expert testimony is necessary to the defendant's case; and 4) the probative value of the expert testimony outweighs its prejudicial effect. Under the second part of the inquiry, the court must determine whether the defendant's right to present the proffered evidence is nonetheless outweighed by the state's compelling interest to exclude the evidence. State v. St. George, 2002 WI 50, 252 Wis. 2d 499, 643 N.W.2d 777, 00-2830.
907.02 Annotation An expert's specious claims about his credentials did not render his testimony incredible or render him unqualified as a matter of law. To hold testimony incredible requires that the expert's testimony be in conflict with the uniform course of nature or with fully established or conceded facts. Questions of reliability are left for the trier of fact. Ricco v. Riva, 2003 WI App 182, 266 Wis. 2d 696, 669 N.W.2d 193, 02-2621.
2021-22 Wisconsin Statutes updated through 2023 Wis. Act 39 and through all Supreme Court and Controlled Substances Board Orders filed before and in effect on November 29, 2023. Published and certified under s. 35.18. Changes effective after November 29, 2023, are designated by NOTES. (Published 11-29-23)