U.S. v. Fields

Brief Filed: 4/05
Court: U.S. Court of Appeals for the Fifth Circuit
Year of Decision: 2007

Read the full-text amicus brief (PDF, 1.98MB)


The Reliability of Expert Testimony in a Death Penalty Case

Index Topic

Expert Witnesses/Psychologists' Competency


This case involves a federal death sentence imposed on defendant-appellant Fields for conviction of a federal capital offense. Fields was sentenced to death largely on the basis of the opinion of a psychiatrist who stated that he could confidently predict Fields would be dangerous in the future. The psychiatrist testified that he did not know of any "standard psychiatric or medical procedures used in arriving at a determination or predicting future dangerousness" and that he was unaware of specific empirical data or studies. He issued his opinion without engaging in any testing or any other objective measures or use of an actuarial method. His basis for this opinion was discussions with the prosecutors and review of some records regarding the defendant. The defense attorney objected to the testimony as unreliable under the standards for expert testimony established by the U.S. Supreme Court in Daubert v. Merrill Dow Pharmaceutical (i.e., that proffered evidence must be grounded in scientific reasoning or methodology). The district court overruled the objections and allowed the expert testimony to go to the jury.

APA's Position

APA submitted an amicus brief to the Court to present relevant scientific knowledge that provides a context for the Court's review of the extent to which a mental health professional reliability can testify in a federal capital case addressing future risk of dangerousness. APA's brief provided background regarding efforts which have been made in the past 50 years to determine the accuracy of predictions of future dangerousness made by psychiatrists and psychologists. The brief apprised the Court regarding the fact that while some progress has been made in developing the means to predict future dangerousness in a community-based setting, the task of assessing the risk of future violence in a secure correctional facility is not sufficiently, scientifically reliable at present to meet the standards necessary for a death penalty case. APA's amicus also briefly addressed the legal standard that should apply to the presentation of expert testimony concerning the likelihood of future violent behavior by the defendant. The brief underscored that predictions of future dangerousness in any setting are not valid if based solely on unstructured clinical judgment, as the psychiatrist used in this case. As a result of both of these points, the psychiatrist's testimony in this case was not in fact based on validated or reliable science and thus was unfairly and inappropriately offered to the jury as "expert" testimony.


On March 29, 2007, the Fifth Circuit affirmed the conviction and death sentence in a lengthy 129-page opinion. The issues by APA (expert testimony and reliability of predictions of future dangerousness) were addressed with specific reference to APA’s brief. The Court rejected the position argued by APA, that the Court adopt the Daubert reliability factors for determining the admissibility of expert evidence offered during the sentencing phases of federal death penalty sentencing hearings. The Court opined that the issues which APA (and Fields) raised were foreclosed by the Supreme Court’s decision in Barefoot v. Estelle.