Issue: “Was the circuit court’s exclusion of the testimony of the defendant’s expert witness an erroneous exercise of discretion, or alternatively, a deprivation of the defendant’s constitutional right to present evidence, as the defendant asserted?” ¶2
Holding: The trial court’s rejection of the expert was based on his lack of extensive experience in the area; however, in considering only the expert’s qualifications and not the defendant’s constitutional right to present a defense, the trial court erroneously exercised discretion. ¶48. A two-part inquiry must be undertaken:
¶54. In the first part of the inquiry, the defendant must satisfy each of the following four factors through an offer of proof. The defendant must show:
1) The testimony of the expert witness met the standards of Wis. Stat. § 907.02 governing the admission of expert testimony.
2) The expert witness’s testimony was clearly relevant to a material issue in this case.
3) The expert witness’s testimony was necessary to the defendant’s case.
4) The probative value of the testimony of the defendant’s expert witness outweighed its prejudicial effect.
¶55. After the defendant successfully satisfies these four factors to establish a constitutional right to present the expert testimony, a court undertakes the second part of the inquiry by determining whether the defendant’s right to present the proffered evidence is nonetheless outweighed by the State’s compelling interest to exclude the evidence.
The test was satisfied; exclusion of the expert was improper. (The merits are fact-intensive. At the risk of oversimplification: The state presented a witness who testified to the percentage of recantations that were ultimately reaffirmed, and a witness who used what he described as a nationally accepted interview technique employing non-leading questions. ¶¶31-32. The excluded expert would have refuted both these claims. ¶34. See also concurrence, ¶¶79-81.