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.
907.02 Annotation Field sobriety tests are not scientific tests. They are merely observational tools that law enforcement officers commonly use to assist them in discerning various indicia of intoxication, the perception of which is necessarily subjective. The procedures an officer employs in determining probable cause for intoxication go to the weight of the evidence, not its admissibility. City of West Bend v. Wilkens, 2005 WI App 36, 278 Wis. 2d 643, 693 N.W.2d 324, 04-1871.
907.02 Annotation The U.S. Supreme Court and Wisconsin Supreme Court have recognized that, although it is not easy to predict future behavior and psychiatrists and psychologists are not infallible, they can opine about future behavior. Brown County v. Shannon R., 2005 WI 160, 286 Wis. 2d 278, 706 N.W.2d 269, 04-1305.
907.02 Annotation The fact that the witness was a forensic scientist did not preclude her from forming an expert opinion about the accuracy of a desk reference based on experience. The forensic scientist properly used the Physician's Desk Reference to presumptively determine the identity of suspected Oxycontin. The result of this presumptive test was supported both by a confirmatory test and other circumstantial evidence. State v. Stank, 2005 WI App 236, 288 Wis. 2d 414, 708 N.W.2d 43, 04-1162.
907.02 Annotation There is no presumption of the admissibility of expert eyewitness testimony in cases involving eyewitness identification. State v. Shomberg, 2006 WI 9, 288 Wis. 2d 1, 709 N.W.2d 370, 04-0630.
907.02 Annotation No expert should be permitted to give an opinion that another mentally and physically competent witness is telling the truth. An opinion that a complainant was sexually assaulted or is telling the truth is impermissible. In asserting that because the complainant was not highly sophisticated she would not have been able to maintain consistency throughout her interview unless it was something that she experienced, a witness testified that the complainant had to have experienced the alleged contact with defendant. The testimony was tantamount to an opinion that the complainant was telling the truth. State v. Krueger, 2008 WI App 162, 314 Wis. 2d 605, 762 N.W.2d 114, 07-2064.
907.02 Annotation Expert testimony must assist the trier of fact to understand the evidence or to determine a fact in issue. A suggested test for deciding when experts may be used is whether the untrained layperson would be qualified to determine intelligently and to the best possible degree the particular issue without enlightenment from those having a specialized understanding of the subject. The proper standard is helpfulness, not absolute necessity. State v. Swope, 2008 WI App 175, 315 Wis. 2d 120, 762 N.W.2d 725, 07-1785.
907.02 Annotation Whether a witness is qualified to give an opinion depends upon whether the witness has superior knowledge in the area in which the precise question lies. State v. Swope, 2008 WI App 175, 315 Wis. 2d 120, 762 N.W.2d 725, 07-1785.
907.02 Annotation Expert testimony is not generally required to prove a party's negligence, and requiring expert testimony before a claim can get to the jury is an extraordinary step that should be ordered only when unusually complex or esoteric issues are before the jury. This principal applies equally to a breach of contract action because it is a general rule that expert testimony is not necessary when the issue is within the realm of the ordinary experience of the average juror. Racine County v. Oracular Milwaukee, Inc., 2009 WI App 58, 317 Wis. 2d 790, 767 N.W.2d 280, 07-2861.
907.02 AnnotationAffirmed. 2010 WI 25, 323 Wis. 2d 682, 781 N.W.2d 88, 07-2861.
907.02 Annotation In an operating while intoxicated (OWI) prosecution, even if a defendant establishes a constitutional right to present an expert opinion that is based in part on portable breath test results, applying the St. George, 2002 WI 50, test, the right to do so is outweighed by the state's compelling interest to exclude that evidence. Permitting the use of that evidence as the basis for an expert opinion would render meaningless the legislature's forbidding of that evidence in OWI prosecutions under s. 343.303, an act that promotes efficient investigations of suspected drunk driving incidents and furthers the state's compelling interest in public safety on its roads. State v. Fischer, 2010 WI 6, 322 Wis. 2d 265, 778 N.W.2d 629, 07-1898.
907.02 Annotation An electronic monitoring device (EMD) report did not present an issue that is particularly complex or unusually esoteric. Additionally, the EMD involves scientific principles that are indisputable and fully within the lay comprehension of the average juror. As such, expert testimony was not required to properly establish a foundation for the report's admissibility. State v. Kandutsch, 2011 WI 78, 336 Wis. 2d 478, 799 N.W.2d 865, 09-1351.
907.02 Annotation The Admissibility of Novel Scientific Evidence: The Current State of the Frye Test in Wisconsin. Van Domelen. 69 MLR 116 (1985).
907.02 Annotation Scientific Evidence in Wisconsin: Using Reliability to Regulate Expert Testimony. Kubiak. 74 MLR 261 (1991).
907.02 Annotation State v. Dean: A Compulsory Process Analysis of the Inadmissibility of Polygraph Evidence. Katz. 1984 WLR 237.
907.02 Annotation The Psychologist as an Expert Witness. Gaines. WBB Apr. 1973.
907.02 Annotation Scientific Evidence in Wisconsin after Daubert. Blinka. Wis. Law. Nov. 1993.
907.02 Annotation The Use and Abuse of Expert Witnesses. Brennan. Wis. Law. Oct. 1997.
907.02 Note NOTE: The above annotations relate to this section as it existed prior to 2011 Wis. Act 2, which added a new standard to sub. (1) and created sub. (2).
907.02 Annotation Expert testimony about retrograde extrapolation of the defendant's blood alcohol concentration was admissible. The court's gate-keeper function is to ensure that the expert's opinion is based on a reliable foundation and is relevant to material issues. The court is to focus on the principles and methodology the expert relies upon, not on the conclusion generated. The question is whether the scientific principles and methods that the expert relies upon have a reliable foundation in the knowledge and experience of the expert's discipline. State v. Giese, 2014 WI App 92, 356 Wis. 2d 796, 854 N.W.2d 687, 13-2009.
907.02 Annotation If experts are in disagreement, it is not for the court to decide which of several competing scientific theories has the best provenance. The accuracy of the facts upon which the expert relies and the ultimate determinations of credibility and accuracy are for the jury, not the court. As stated in Daubert, 509 U.S. 579 (1993), vigorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence. State v. Giese, 2014 WI App 92, 356 Wis. 2d 796, 854 N.W.2d 687, 13-2009.
2021-22 Wisconsin Statutes updated through 2023 Wis. Act 240 and through all Supreme Court and Controlled Substances Board Orders filed before and in effect on May 30, 2024. Published and certified under s. 35.18. Changes effective after May 30, 2024, are designated by NOTES. (Published 5-30-24)