Experts’ testimony quizzed

Press, 19 July 1988, Page 23

Experts’ testimony quizzed

NZPA-AP Washington A courtroom decision made by flipping a coin can often be more accurate than one based on the judgment of psychologists and psychiatrists, according to a United States study. David Faust, an associate professor of psychology at Brown University, and Jay Ziskin, a Californian lawyer and psychologist, said in a “Science” journal article that jurors or other citizens can make psychological judgments as accurately as the professionals, "thus raising substantial doubt that psychologists or psychiatrists meet legal standards for expertise.”

Psychological experts are often used in United States criminal trials to assess the mental health and the potential for violence of defendants.

In many states, the punishment phase of capital murder trials takes into consideration a prediction of the continued violent

behaviour of the defendant. Often the state calls on psychologists or psychiatrists for opinons. But Professor Faust, in an interview, said the accuracy of these opinions is questionable. “A large degree of error has been demonstrated. In many studies the error rate well exceeds the accuracy rate,” Professor Faust said. “There is virtually no evidence that experts are any better equipped to make those judgments than are lay individuals.” In the “Science” article, Professor Faust and Mr Ziskin cited a series of studies that they said showed “clinicians are wrong at least twice as often as they are correct,” in predicting violent behaviour.

They said one study followed 967 patients who had been placed in maximum securities hospitals on the basis of a psychiatric determination of dangerousness. They were

later transferred to ordinary mental hospitals. After four years, only half of the group was still in the hospitals and only 26 patients who had been judged as potentially violent had actually committed violent acts during that time. In the article, the authors said they conducted their research to learn if expert psychological witnesses achieve “reasonable certainty” of facts and aid in establishing the truth in trials. Psychological clinicians are often unable to agree on psychiatric diagnoses, “much less trustworthy answers to ... more diffir cult forensic questions, which often demand projections backward and forward in time.” Expert testimony can often have what the article called “a prejudicial effect on juries.” “Confidence and accuracy can be inversely related, and yet the jury may well accept the

opinion of an expert who exudes confidence over that of an opposing expert who expresses appropriate caution,” the authors said. Other experts said the question of reliability of psychological testimony has been a matter of controversy, but that it is not clear that such expertise is as unreliable as Professor Faust and Mr Ziskin contend. “I don’t know of an opinion like that that is generally accepted in the scientific community,” said James C. Miller, a Professor of Psychology at the George Washington University. “That is a controversial position.” Dr Jon O’Brien, a forensic psychiatry expert at Georgetown University, said, “No professional could give a guarantee that an individual will or will not act violently.” But he said seeking truth in trials can still benefit from the testimony of experts.