Wis. Stat. § 906.06
Verdict impeachment requires evidence that is: 1) competent; 2) shows substantive grounds sufficient to overturn the verdict; and 3) shows resulting prejudice. Impeachment of a verdict through juror affidavits or testimony is discussed. After Hour Welding v. Lanceil Management Co., 108 Wis. 2d 734, 324 N.W.2d 686 (1982). There was probable prejudice when the question of a depraved mind was central and a juror went to the jury room with a dictionary definition of "depraved" written on a card. State v. Ott, 111 Wis. 2d 691, 331 N.W.2d 629 (Ct. App. 1983). A conviction was reversed when extraneous information improperly brought to the jury's attention raised a reasonable possibility that the information had a prejudicial effect on the hypothetical average jury. State v. Poh, 116 Wis. 2d 510, 343 N.W.2d 108 (1984). Evidence of a juror's racially-prejudiced remark during jury deliberations was not competent under sub. (2). State v. Shillcutt, 119 Wis. 2d 788, 350 N.W.2d 686 (1984). In any jury trial, material prejudice on the part of any juror impairs the right to a jury trial. That prejudicial material was brought to only one juror's attention and was not communicated to any other jurors is irrelevant to determining whether that information was "improperly brought to the jury's attention" under sub. (2). Castenada v. Pederson, 185 Wis. 2d 200, 518 N.W.2d 246 (1994), State v. Messelt, 185 Wis. 2d 255, 518 N.W.2d 232 (1994). Extraneous information is information, other than the general wisdom that a juror is expected to possess, that a juror obtains from a non-evidentiary source. A juror who consciously brings non-evidentiary objects to show the other jurors improperly brings extraneous information before the jury. State v. Eison, 188 Wis. 2d 298, 525 N.W.2d 91 (Ct. App. 1994). Sub. (2) does not limit the testimony of a juror regarding clerical errors in a verdict. A written verdict not reflecting the jury's oral decision may be impeached by showing in a timely manner and beyond a reasonable doubt that all jurors are in agreement that an error was made. State v. Williquette, 190 Wis. 2d 678, 526 N.W.2d 144 (Ct. App. 1995). An analytical framework to be used to determine whether a new trial on the grounds of prejudice due to extraneous juror information is outlined. State v. Eison, 194 Wis. 2d 160, 533 N.W.2d 738 (1995). Jurors may rely on their common sense and life experience during deliberations, including expertise that a juror may have on a particular subject. That a juror was a pharmacist did not make his knowledge about the particular effect of a drug extraneous information subject to inquiry under sub. (2). State v. Heitkemper, 196 Wis. 2d 218, 538 N.W.2d 561 (Ct. App. 1995), 94-2659. The extraneous information exception under sub. (2) is not limited to factual information but also includes legal information obtained outside the proceeding. State v. Wulff, 200 Wis. 2d 318, 546 N.W.2d 522 (Ct. App. 1996), 95-1732. Generally, the sole area jurors are competent to testify to is whether extraneous information was considered. Except when juror bias goes to a fundamental issue such as religion, evidence of juror perceptions is not competent, no matter how mistaken, and cannot form the basis for granting a new trial. Anderson v. Burnett County, 207 Wis. 2d 587, 558 N.W.2d 636 (Ct. App. 1996), 96-0954. The trial court, and not the defendant or the defendant's attorney, is permitted to question a juror directly at a hearing regarding juror bias. The trial court's discretion in submitting questions suggested by the defendant is limited, but the failure to submit questions is subject to harmless error evaluation. State v. Delgado, 215 Wis. 2d 16, 572 N.W.2d 479 (Ct. App. 1997), 96-2194. It was reasonable to refuse to allow a former member of the jury from testifying as a witness in the same case. Broadhead v. State Farm Mutual Insurance Co., 217 Wis. 2d 231, 579 N.W.2d 761 (Ct. App. 1998), 97-0904. For a juror to be competent to testify regarding extraneous information brought to the jury within the sub. (2) exception, the information must be potentially prejudicial, which it may be if it conceivably relates to a central issue of the trial. After determining whether testimony is competent under sub. (2), the court must find clear, satisfactory, and convincing evidence that the juror heard or made the comments alleged, and if it does, must then decide whether prejudicial error requiring reversal exists. State v. Broomfield, 223 Wis. 2d 465, 589 N.W.2d 225 (1999), 97-0520. There is no bright line rule regarding the time lag between the return of a verdict and when evidence of a clerical error in a verdict must be obtained or be rendered insufficiently trustworthy. Grice Engineering, Inc. v. Szyjewski, 2002 WI App 104, 254 Wis. 2d 743, 648 N.W.2d 487, 01-0073. Proof beyond a reasonable doubt to impeach a civil jury trial may be supplied by showing that five-sixths of the jurors agree that the reported verdict is in error and agree on the corrected verdict, provided each of these jurors was a part of the original group in favor of the verdict. This approach meets the "all of the jurors" requirement in Williquette. Grice Engineering, Inc. v. Szyjewski, 2002 WI App 104, 254 Wis. 2d 743, 648 N.W.2d 487, 01-0073. When a motion for a new trial is based on prejudicial extraneous information, the circuit court may grant an evidentiary hearing upon an affidavit that shows juror statements that are competent testimony and, if believed, are clear and convincing evidence of extraneous information that is potentially prejudicial. The hearing may be used to evaluate the credibility of the initial statements and to obtain additional competent testimony bearing on prejudice, such as the specific nature of the extraneous evidence and the circumstances under which it came to the jury's attention. Juror testimony on the effect of extraneous information is not competent. Manke v. Physicians Insurance Co., 2006 WI App 50, 289 Wis. 2d 750, 712 N.W.2d 40, 05-1103 A specific dictionary definition of a word, even a common word, is not the type of general knowledge or accumulated life experiences that jurors are expected to possess. The dictionary definition of a word brought to the jury room and read aloud by a juror, was extraneous information. There is no presumption that a hypothetical average juror would follow a jury instruction rather than a dictionary definition brought in by a juror. Instead, a court should base its prejudice analysis on a comparison of the jury instruction with the dictionary definition and on other relevant circumstances. Manke v. Physicians Insurance Co., 2006 WI App 50, 289 Wis. 2d 750, 712 N.W.2d 40, 05-1103. When a juror makes a clear statement that indicates that he or she relied on racial stereotypes or animus to convict a criminal defendant, the 6th amendment requires that the no-impeachment rule give way in order to permit the trial court to consider the evidence of the juror's statement and any resulting denial of the jury trial guarantee. For the inquiry to proceed, there must be a showing that one or more jurors made statements exhibiting overt racial bias that cast serious doubt on the fairness and impartiality of the jury's deliberations and resulting verdict. To qualify, the statement must tend to show that racial animus was a significant motivating factor in the juror's vote to convict. Pena-Rodriguez v. Colorado, 580 U.S. ___, 137 S. Ct. 855, 197 L. Ed. 2d 107 (2017).