Minnesota Supreme Court Holds Frye Inapplicable to Expert Evidence on Battered Child Syndrome

The Supreme Court of Minnesota has ruled that Frye is inapplicable to expert testimony on "battered child syndrome." See State v. MacLennan, No. A03-1048 (Minn. Aug. 18, 2005). More broadly, the court's opinion distinguishes techniques and procedures based on chemical, biological, and other physical science, on the one hand, from theories and assumptions based on the behavioral sciences, on the other. In the case of technical testimony from the hard sciences, the trier of fact may often be unable, the opinion suggests, to understand the specialized tests and fancy methods on which expert opinion is reliant. With social science testimony, by contrast, the trier of fact may be more able to evaluate the testimony by recourse to its general education and common sense, because such testimony typically involves explanations for human behavior.

The Frye standard is particularly unsuitable, says the MacLennan opinion, for "syndrome" evidence, in which the expert is not permitted (in Minnesota, anyway) to opine on whether the individual actually suffers from the relevant syndrome. A "syndrome" expert may testify (in Minnesota, anyway) only in general terms, by way of describing the syndrome's typical features. The admissibility of such testimony, under MacLennan, should depend on whether it satisfies Minn. R. Evid. 702, which focuses inquiry primarily on whether the evidence will assist the jury.