Coble v. Texas

Brief Filed: 5/11
Court: U.S. Supreme Court
Year of Decision: N/A – Certiorari not accepted

Read full-text amicus brief (PDF, 104KB)


The reliability of expert testimony (on risk of “future dangerousness”) in a death penalty case

Index Topic

Expert Witnesses/Psychologists' Competency


After 18 years on death row for conviction of capital murder for the shooting deaths of his wife’s mother, father and brother, Billie Wayne Coble, a Texas death row inmate, was re-sentenced to death at a new sentencing hearing. The rehearing was awarded due in part to an unconstitutional jury charge in his first trial, in part based on the testimony of the State's “future dangerousness” expert, Dr. Richard Coons (a forensic psychiatrist). Dr. Coons’ testimony in the rehearing was rebutted by appellant’s expert, Dr. Mark Cunningham, who served as primary consultant for a prior APA briefing in U.S. v. Fields addressing prediction of dangerousness. The Texas Court of Criminal Appeals found the admission of Dr. Coons’ testimony to be in error because it was not scientifically valid (he had not met with Coble in 18 years and had no validated approach to his assessment) and was unreliable, but then went on to find no Eighth Amendment violation of Coble’s rights, citing Barefoot v. Estelle. Because the Texas Court did not find constitutional error, it applied the more lenient harmless error standard and held that the admission of the testimony that the defendant had a likelihood of engaging in dangerous behavior in the future—which lead to the imposition of the death penalty—did not have a “substantial and injurious” effect upon the jury’s deliberations concerning the issue of future dangerousness.

APA was asked to file a brief asking the U.S. Supreme Court to review the decision by the Court of Criminal Appeals finding that the expert evidence presented by the prosecution on the question of whether the defendant was likely to pose a risk of future dangerousness was inherently unreliable but that the admission of the evidence was harmless error. 

APA's Position

The issues presented in this case are directly relevant to the brief APA filed in an earlier Texas death penalty case (U.S. v. Fields). Much of the work on the state of research-based risk assessment for future dangerousness included in that brief provided the foundation for the brief in this case and indeed the same testimony at issue in this case was also provided by Dr. Coons in U.S. v. Fields. APA submitted this brief to present scientific knowledge that provides a context for the Court’s consideration of whether admitting unreliable expert testimony in a particular capital sentencing proceeding can constitute constitutional error. APA supports the grant of a writ of certiorari because the integrity of the legal system and the mental health profession are undermined if unscientific, unreliable, but purportedly expert testimony about future dangerousness is deemed constitutionally admissible in capital sentencing. The brief addresses the following: 1) unstructured clinical testimony like that at issue is not based on science and should not be relied upon to establish future dangerousness; 2) in contrast to Dr. Coons’ unstructured approach, structured risk-assessment methods are scientifically based and can reliably inform assessments of future dangerousness in a variety of contexts; and 3) unstructured clinical risk-assessment testimony is unduly persuasive to juries.


On June 20, 2011, the U.S. Supreme Court denied Mr. Coble’s petition for certiorari. The denial was likely due to the factors that made a grant a challenge from the start: the lack of conflict among the federal appellate or state courts on the issue and the difficulty in reopening (or at least reexamining) Barefoot v. Estelle. We believe that the APA brief will be helpful in future litigation.