Chapter 907

907.02 Annotation The admissibility of expert testimony is governed by this section. The court’s role with regard to the admissibility of evidence is often described as that of a gatekeeper. Before 2011 Wis. Act 2, the court’s role was simply to determine whether the evidence made a fact of consequence more or less probable. The heightened standard under this amended section does not change this gatekeeping function. It does, however, require more of the gatekeeper. Instead of simply determining whether the evidence makes a fact of consequence more or less probable, courts must now also make a threshold determination as to whether the evidence is reliable enough to go to the factfinder. State v. Jones, 2018 WI 44, 381 Wis. 2d 284, 911 N.W.2d 97, 15-2665.

907.02 Annotation Expert testimony at a Machner, 92 Wis. 2d 797 (1979), hearing regarding the reasonableness of trial counsel’s performance is admissible, but only to the extent the expert focuses on factual matters and does not offer the expert’s opinion on the reasonableness of trial counsel’s conduct or strategy. Expert testimony is admissible to address questions of fact, not law. State v. Pico, 2018 WI 66, 382 Wis. 2d 273, 914 N.W.2d 95, 15-1799.

907.02 Annotation Sub. (1) continues to permit an expert witness to testify in the form of an opinion “or otherwise,” including exposition testimony on general principles without explicitly applying those principles to, or even having knowledge of, the specific facts in the case. If an expert testifies in the form of an opinion, then the expert must apply the principles and methods reliably to the facts of the case. State v. Dobbs, 2020 WI 64, 392 Wis. 2d 505, 945 N.W.2d 609, 18-0319.

907.02 Annotation When expert testimony is proffered in the form of an exposition on general principles, the circuit court, as gatekeeper, must consider the following four factors: 1) whether the expert is qualified; 2) whether the testimony will address a subject matter on which the factfinder can be assisted by an expert; 3) whether the testimony is reliable; and 4) whether the testimony will fit the facts of the case. State v. Dobbs, 2020 WI 64, 392 Wis. 2d 505, 945 N.W.2d 609, 18-0319.

907.02 Annotation There is no categorical rule that would condition the admissibility of relevant canine scent evidence on there being physical or forensic evidence corroborating the dog alerts. Rather, expert testimony regarding dog alerts, like all other expert testimony, may be admitted if the court concludes the evidence satisfies the threshold reliability criteria in this section and is not otherwise subject to exclusion under s. 904.03. State v. Bucki, 2020 WI App 43, 393 Wis. 2d 434, 947 N.W.2d 152, 18-0999.

907.02 Annotation Sub. (1) requires the trial court to determine, by a preponderance of the evidence and according to whichever criteria it deems appropriate, that the proffered expert testimony is based on adequate facts and a sound methodology and is thus sufficiently reliable to go before a jury. Personal knowledge and experience may form the basis for expert testimony. In certain fields, experience is the predominant, if not sole, basis for a great deal of reliable expert testimony. To assess reliability in this context, the witness must explain how the experience leads to the conclusion reached, why that experience is a sufficient basis for the opinion, and how that experience is reliably applied to the facts. State v. Hogan, 2021 WI App 24, 397 Wis. 2d 171, 959 N.W.2d 658, 19-2350.

907.02 Annotation Given the widespread availability of Fitbits and other similar wireless step-counting devices in today’s consumer marketplace, the circuit court in this case reasonably concluded Fitbit evidence was not so unusually complex or esoteric that the jury needed an expert to understand it. State v. Burch, 2021 WI 68, 398 Wis. 2d 1, 961 N.W.2d 314, 19-1404.

907.02 Annotation Improper vouching occurs when a witness’s testimony implicitly suggests that the witness believes another witness’s testimony is truthful. In this case, the testimony of two witnesses bore both of the hallmarks likely to turn statistical testimony about the prevalence of false reports of sexual assault into improper vouching: 1) both witnesses testified to a greater than 99 percent truthful reporting rate—a percentage that provided a mathematical statement approaching certainty that false reporting simply does not occur—and 2) one witness also recounted the witness’s extensive personal interactions with the victim—testimony that would inevitably be seen by the jury as a personal or particularized endorsement of the victim’s credibility. State v. Mader, 2023 WI App 35, 408 Wis. 2d 632, 993 N.W.2d 761, 22-0382.

907.02 Annotation The Daubert Standard in Wisconsin: A Primer. Blinka. Wis. Law. Mar. 2011.

907.02 Annotation Guarding the Gate: Six Years of Daubert in Wisconsin Courts. Aprahamian. Wis. Law. Mar. 2017.

907.03 907.03 Bases of opinion testimony by experts. The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or made known to the expert at or before the hearing. If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, the facts or data need not be admissible in evidence in order for the opinion or inference to be admitted. Facts or data that are otherwise inadmissible may not be disclosed to the jury by the proponent of the opinion or inference unless the court determines that their probative value in assisting the jury to evaluate the expert’s opinion or inference substantially outweighs their prejudicial effect.

907.03 History History: Sup. Ct. Order, 59 Wis. 2d R1, R208 (1973); 1991 a. 32; 2011 a. 2.

907.03 Annotation The trial court properly admitted the opinion of a qualified electrical engineer although he relied on a pamphlet objected to as inadmissible hearsay. E.D. Wesley Co. v. City of New Berlin, 62 Wis. 2d 668, 215 N.W.2d 657 (1974).

907.03 Annotation A chiropractor could testify as to a patient’s self-serving statements when those statements were used to form his medical opinion. Klingman v. Kruschke, 115 Wis. 2d 124, 339 N.W.2d 603 (Ct. App. 1983).

907.03 Annotation The trial court erred by barring expert testimony on impaired future earning capacity based on government surveys. Brain v. Mann, 129 Wis. 2d 447, 385 N.W.2d 227 (Ct. App. 1986).

907.03 Annotation While opinion evidence may be based upon hearsay, the underlying hearsay data may not be admitted unless it is otherwise admissible under a hearsay exception. State v. Weber, 174 Wis. 2d 98, 496 N.W.2d 762 (Ct. App. 1993).

907.03 Annotation Although this section allows an expert to base an opinion on hearsay, it does not transform the testimony into admissible evidence. The court must determine when the underlying hearsay may reach the trier of fact through examination of the expert, with cautioning instructions, and when it must be excluded altogether. State v. Watson, 227 Wis. 2d 167, 595 N.W.2d 403 (1999), 95-1067.

907.03 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.

907.03 Annotation This section implicitly recognizes that an expert’s opinion may be based in part on the results of scientific tests or studies that are not his or her own. State v. Williams, 2002 WI 58, 253 Wis. 2d 99, 644 N.W.2d 919, 00-3065.

907.03 Annotation Medical experts may rely on the reports and medical records of others in forming opinions that are within the scope of their own expertise. Enea v. Linn, 2002 WI App 185, 256 Wis. 2d 714, 650 N.W.2d 315, 01-2781.

907.03 Annotation This section does not give license to the proponent of an expert to use the expert solely as a conduit for the hearsay opinions of others. As in a civil proceeding there is no independent right to confront and cross-examine expert witnesses under the state and federal constitutions. Procedures used to appoint a guardian and protectively place an individual must conform to the essentials of due process. Walworth County v. Therese B., 2003 WI App 223, 267 Wis. 2d 310, 671 N.W.2d 377, 03-0967.

907.03 Annotation This section is not a hearsay exception and does not make inadmissible hearsay admissible but makes an expert’s opinion admissible even if the expert has relied on inadmissible hearsay in arriving at the opinion, as long as the hearsay is the type of facts or data reasonably relied on by experts in the particular field in forming opinions on the subject. A circuit court must be given latitude to determine when the underlying hearsay may be permitted to reach the trier of fact through examination of the expert with cautioning instructions for the trier of fact to head off misunderstanding and when it must be rigorously excluded altogether. Staskal v. Wausau General Insurance Co., 2005 WI App 216, 287 Wis. 2d 511, 706 N.W.2d 311, 04-0663.

907.03 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.

907.03 Annotation That part of this section that a properly qualified expert witness may rely on inadmissible material if that material is of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, rests on the commonsense reality that a testifying expert could not be required to replicate all of the experiments and personally make all of the observations either underlying the development of the expert’s field or otherwise relevant to the expert’s opinion. Permitting the expert to rely on inadmissible material in accordance with this section does not violate a defendant’s right to confrontation. State v. Heine, 2014 WI App 32, 354 Wis. 2d 1, 844 N.W.2d 409, 13-1022.

907.03 Annotation The disclosure of otherwise inadmissible information under this section is to assist the jury in evaluating the expert’s opinion, not to prove the substantive truth of the otherwise inadmissible information. In this case, the state’s reference to the DNA evidence during closing arguments was a shift from a non-hearsay impeachment purpose to a substantive use to prove the truth of the matter asserted. The DNA evidence was inadmissible hearsay, and it was erroneously received during trial and closing argument as no limiting instructions were given to the jury as to its consideration of the DNA evidence. The DNA evidence, at a minimum, could not be presented to the jury without proper limiting instructions and could not be used by the state as substantive evidence. State v. Thomas, 2021 WI App 55, 399 Wis. 2d 277, 963 N.W.2d 887, 20-0032.

907.03 Annotation Affirmed on other grounds. 2023 WI 9, 405 Wis. 2d 654, 985 N.W.2d 87, 20-0032.

907.03 Annotation An Evaluation of Drug Testing Procedures Used by Forensic Laboratories and the Qualifications of Their Analysts. Stein, Laessig, & Indriksons. 1973 WLR 727.

907.04 907.04 Opinion on ultimate issue. Testimony in the form of an opinion or inference otherwise admissible is not objectionable because it embraces an ultimate issue to be decided by the trier of fact.

907.04 History History: Sup. Ct. Order, 59 Wis. 2d R1, R211 (1973).

907.05 907.05 Disclosure of facts or data underlying expert opinion. The expert may testify in terms of opinion or inference and give the reasons therefor without prior disclosure of the underlying facts or data, unless the judge requires otherwise. The expert may in any event be required to disclose the underlying facts or data on cross-examination.

907.05 History History: Sup. Ct. Order, 59 Wis. 2d R1, R213 (1973); 1991 a. 32.

907.06 907.06 Court appointed experts.

907.06(1) (1) Appointment. The judge may on the judge’s own motion or on the motion of any party enter an order to show cause why expert witnesses should not be appointed, and may request the parties to submit nominations. The judge may appoint any expert witnesses agreed upon by the parties, and may appoint witnesses of the judge’s own selection. An expert witness shall not be appointed by the judge unless the expert witness consents to act. A witness so appointed shall be informed of the witness’s duties by the judge in writing, a copy of which shall be filed with the clerk, or at a conference in which the parties shall have opportunity to participate. A witness so appointed shall advise the parties of the witness’s findings, if any; the witness’s deposition may be taken by any party; and the witness may be called to testify by the judge or any party. The witness shall be subject to cross-examination by each party, including a party calling the expert witness as a witness.

907.06(2) (2) Compensation. Expert witnesses so appointed are entitled to reasonable compensation in whatever sum the judge may allow. The compensation thus fixed is payable from funds which may be provided by law in criminal cases and cases involving just compensation under ch. 32. In civil cases the compensation shall be paid by the parties in such proportion and at such time as the judge directs, and thereafter charged in like manner as other costs but without the limitation upon expert witness fees prescribed by s. 814.04 (2).

907.06(3) (3) Disclosure of appointment. In the exercise of discretion, the judge may authorize disclosure to the jury of the fact that the court appointed the expert witness.

907.06(4) (4) Parties’ experts of own selection. Nothing in this rule limits the parties in calling expert witnesses of their own selection.

907.06(5) (5) Appointment in criminal cases. This section shall not apply to the appointment of experts as provided by s. 971.16.

907.06 History History: Sup. Ct. Order, 59 Wis. 2d R1, R215 (1973); Sup. Ct. Order, 67 Wis. 2d 784; 1991 a. 32.

907.06 Annotation As sub. (1) prevents a court from compelling an expert to testify, it logically follows that a litigant should not be able to so compel an expert and a privilege to refuse to testify is implied. Burnett v. Alt, 224 Wis. 2d 72, 589 N.W.2d 21 (1999), 96-3356.

907.06 Annotation Under Alt, 224 Wis. 2d 72 (1999), a person asserting the privilege not to offer expert opinion testimony can be required to give that testimony only if: 1) there are compelling circumstances present; 2) there is a plan for reasonable compensation of the expert; and 3) the expert will not be required to do additional preparation for the testimony. An exact question requiring expert opinion testimony and a clear assertion of the privilege are required for a court to decide whether compelling circumstances exist. Alt does not apply to observations made by a person’s treating physician relating to the care or treatment provided to the patient. Glenn v. Plante, 2004 WI 24, 269 Wis. 2d 575, 676 N.W.2d 413, 02-1426.

907.06 Annotation Under Alt, 224 Wis. 2d 72 (1999), and Glenn, 2004 WI 24, a medical witness must testify about the witness’s own conduct relevant to the case, including observations and thought processes, treatment of the patient, why certain actions were taken, what institutional rules the witness believed applied, and the witness’s training and education pertaining to the relevant subject. Subject to the compelling need exception recognized in Alt and Glenn, a medical witness who is unwilling to testify as an expert cannot be forced to give an opinion of the standard of care applicable to another person or of the treatment provided by another person. A medical witness who is alleged to have caused injury to the plaintiff by medical negligence may be required to give an opinion on the standard of care governing the witness’s own conduct. Carney-Hayes v. Northwest Wisconsin Home Care, Inc., 2005 WI 118, 284 Wis. 2d 56, 699 N.W.2d 524, 03-1801.

907.07 907.07 Reading of report by expert. An expert witness may at the trial read in evidence any report which the witness made or joined in making except matter therein which would not be admissible if offered as oral testimony by the witness. Before its use, a copy of the report shall be provided to the opponent.

907.07 History History: Sup. Ct. Order, 59 Wis. 2d R1, R219 (1973); 1991 a. 32.