"The circuit court excluded the testimony of two experts regarding the occurrence of false confessions and the police interrogation techniques likely to generate them as well as the psychological characteristics of defendant that allegedly made him more susceptible to these techniques.
We hold that the circuit court did not abuse its discretion by excluding the expert testimony regarding the published literature on false confessions and police interrogations on the basis of its determination that the testimony was not reliable, even though the subject of the proposed testimony is beyond the common knowledge of the average juror."
From the Supreme Court's opinion:
"The circuit court examined the manner in which Leo analyzed the confessions that he determined to be false:
[Leo] starts with the conclusion that the confession is false and then he works backwards.... He doesn't take into consideration why someone might falsely confess, other than because of a police interrogation technique.... [A]nd there are reasons why people would falsely confess, they might be trying to protect someone.... He hasn't determined a reliable means to have a study group consist of innocent people who wrongfully confess that weren't mentally ill or youth.
The circuit court criticized this methodology for failing to compare true and false confessions and identify factors that contribute to false confessions but not true confessions. As the circuit court stated, "[I]f true and false confessions can be derived from the same police interrogation techniques, [how] is it possible to blame police interrogation techniques with any degree of reliability?" Given what the circuit court considered to be inadequacies of Leo's data and methodology, the circuit court concluded that Leo's testimony was unreliable.
Nothing in the circuit court's analysis placed the exclusion of Leo's testimony outside the range of principled outcomes. The circuit court properly considered all stages of Leo's analysis and found it unreliable at every stage. With regard to the data underlying Leo's testimony, the circuit court reasonably determined that its sources were unreliable because they were prone to inaccuracy or bias and, in nearly all instances, had not been subjected to the rigorous standards of scientific peer-review. Additionally, the circuit court raised multiple legitimate concerns about the "manner in which [Leo] interpret[ed] and extrapolate[d] from those data." The unreliable methodology, as the circuit court described, resulted in conclusions consistent with Leo's own preconceived beliefs rather than testable results consistent with an objective, scientific process. Therefore, because the exclusion of Leo's testimony was a reasonable and principled outcome, the circuit court's decision did not amount to an abuse of discretion. The Court of Appeals came to the same conclusion after making similar observations about the data and methods underlying Leo's studies, and we thus affirm the lower courts' decisions to exclude Leo's testimony