Instructed preadolescents to "fake bad" on comprehensive neuropsychological testing, then had cases reviewed by 42 clinical neuropsychologists. Ninety-three percent of reviewers diagnosed abnormality, most attributing results to cortical dysfunction; no clinician detected malingering. Results are consistent with other studies exploring capacity of adolescents and adults to fake believable deficits on neuropsychological testing. (Author/NB)