805.18 Mistakes and omissions; harmless error.

(1) The court shall, in every stage of an action, disregard any error or defect in the pleadings or proceedings which shall not affect the substantial rights of the adverse party.

(2) No judgment shall be reversed or set aside or new trial granted in any action or proceeding on the ground of selection or misdirection of the jury, or the improper admission of evidence, or for error as to any matter of pleading or procedure, unless in the opinion of the court to which the application is made, after an examination of the entire action or proceeding, it shall appear that the error complained of has affected the substantial rights of the party seeking to reverse or set aside the judgment, or to secure a new trial.

History: Sup. Ct. Order, 67 Wis. 2d 585, 714 (1975); Sup. Ct. Order No. 96-08, 207 Wis. 2d xv (1997).

For an error to “affect the substantial rights" of a party, there must be a reasonable possibility that the error contributed to the outcome of the action. A reasonable possibility of a different outcome is a possibility sufficient to undermine confidence in the outcome. If the error at issue is not sufficient to undermine the reviewing court's confidence in the outcome of the proceeding, the error is harmless. Evelyn C.R. v. Tykila S. 2001 WI 110, 246 Wis. 2d 1, 629 N.W.2d 768, 00-1739.

Error is harmless if it is clear beyond a reasonable doubt that a rational jury would have found the defendant guilty absent the error. State v. Harvey, 2002 WI 93, 254 Wis. 2d 442, 647 N.W.2d 189, 00-0541.

Section 971.08 (2), requiring vacation of judgment and permission to withdraw a pleas in the event of improper notice of the consequences of a plea on immigration and naturalization, is subject to harmless error analysis under s. 971.26 and this section. State v. Douangmala, 2002 WI 62, was objectively wrong because it failed to properly consider s. 971.26 and this section and is thus overruled. The mandatory “shall" in sub. (2) did not control as both of the harmless error savings statutes also use the mandatory “shall" language. All of the relevant statutes use “shall," and, accordingly, none is “more mandatory" than any other. Sections 971.08(2) and 971.26 and this section are most comprehensibly harmonized by applying harmless error analysis. State v. Reyes Fuerte, 2017 WI 104, 378 Wis. 2d 504, 904 N.W.2d 773, 15-2041.