9th Circuit Affirms Exclusion of Testimony Based on Abel Assessment of Sexual Interest

In an unpublished opinion, the Ninth Circuit has affirmed the district court's ruling, in a child molestation case, excluding testimony from a defense expert who relied on the Abel Assessment of Sexual Interest ("AASI"), an instrument sometimes used to gauge whether the subject shows an unusual level of sexual attraction to children. The panel accepted five reasons offered by the district court for excluding the testimony as unreliable:

(1) the AASI test is a psychological instrument to be used for treatment, not for diagnostic purposes, and it is not designed to assess the tendency of a person to abuse children sexually; (2) Dr. Abel did not use a control group and it is unclear how or whether the test ferrets out "fakers"; (3) the test has not been subject to adequate peer review because Dr. Abel has proprietary rights over the test and has not shared his formula with other scientists (and those who have tried to assess the test's validity have come up with dubious and inconsistent results); (4) the potential error rate "varies from poor ... to appalling," which makes it an unreliable instrument; and (5) the relevant scientific community does not generally accept the AASI test as a diagnostic test for pedophilia.

See United States v. Birdsbill, No. 03-30204 (9th Cir. May 4, 2004) (Canby, Wardlaw, & Gould, JJ.).