Judicial Notebook

A recent decision of the Appeals Court of Massachusetts has dealt a legal blow to a widely used sex offender assessment tool, the Abel Assessment for Sexual Interest (AASI). In 2005, in Ready v. Commonwealth (824 N.E.2d 474), the appellate court affirmed a trial court's 2002 exclusion of AASI results in a case in which a convicted sex offender, Gerard Ready, was seeking release from the Massachusetts Treatment Center for Sexually Dangerous Persons.

Ready had been convicted of multiple counts of raping and sexually assaulting children. Over the course of 19 years of confinement, Ready admitted perpetrating as many as 1,000 child sexual assaults. Also, during his confinement, authorities found numerous letters Ready had written expressing his sexual interest in boys and referring to his continuing attempts to acquire lewd materials.

In his effort to persuade a state court that he was no longer "sexually dangerous," Ready offered proof of his performance on the AASI. As described by the trial court, the "AASI is a multi-part assessment device that combines the theory of 'visual reaction time'…with a subject's self-reported sexual arousal to slide photograph stimuli. [The AASI] purports to measure a subject's sexual interest in people of various ages [and] may only be purchased from…Abel Screening Inc., a for-profit company….Further, all users of the AASI must send all of their raw data to Abel Screening Inc. for processing."

The court further noted that according to its creator, Dr. Gene Abel, "the AASI, in some form, has been administered over 34,000 times and is or has been used by over 300 sites."

Science or wizardry?

Responding to the state's motion to exclude Ready's AASI results from evidence, the trial court applied several standards for the admissibility of scientific evidence laid down by the U.S. Supreme Court in Daubert v. Merrell Dow Pharmaceuticals Inc. (509 U.S. 579 [1993]).

The court first reviewed the limited published studies of the AASI and held that "the theories and techniques underlying the AASI have not been sufficiently tested for admissibility in this proceeding." In the sarcastic words of the court, after noting that the AASI is a proprietary instrument whose underlying formulas are not released to other professionals: "For all we know, they and their components could be mathematically based, founded upon indisputable empirical research, or simply the magic of young Harry Potter's mixing potions at the Hogwarts School of Witchcraft and Wizardry."

In examining the AASIs error rate in light of Daubert, the court concluded that "the AASI's high error rate, coupled with Dr. Abel's solution to the error rate, which is to merely 'lower the cut-off score' (thereby erroneously labeling non-molesters as molesters), substantially detracts from the petitioner's contention that the AASI is scientifically sound and sufficiently reliable to assist the trier of fact."

Considering the standard of "general acceptance," the trial court held that Ready "has not proffered any credible evidence of the AASI's acceptance in the scientific community."

Finally, applying the Daubert standard of "relevance"-i.e., whether the proffered evidence is "sufficiently tied to the facts of the case"-the trial court concluded that no evidence supports the use of the AASI in sexually dangerous person or sexually violent predator proceedings and found no evidence that the relevant scientific community supports its use to predict whether a sex offender is likely to reoffend sexually if released to the community. In fact, the court noted that Dr. Abel admitted that the AASI cannot predict reoffense and that a Relapse Prediction Score Dr. Abel was developing did not meet evidentiary standards for admissibility.


Finding adequate support in the record for the judge's decision, the appeals court affirmed exclusion of the AASI in Ready. The Massachusetts Supreme Judicial Court then refused to review the appeals court's decision.

Some might regard the courts' decisions in Ready as prime examples of the legal maxim that "hard cases make bad law." After all, the facts in the case were repulsive, to say the least, and there was little in the way of sympathy for the petitioner. Moreover, given the nature of Ready's claim, this was hardly the ideal case to argue that the AASI was "relevant," as the law defines that term.

The AASI continues to be widely used by psychologists and others as a measure of sexual interest in children, and the courts in Ready expressed no view regarding the admissibility of its results in other contexts. There is no doubt, however, that the courts' opinions in Ready will add fuel to the future legal debate over the admissibility of AASI results and may encourage courts to take a similarly tough position with regard to other psychological assessment tools used in this difficult area of practice.

Judicial Notebook is a project of APA's Div. 9 (Society for the Psychological Study of Social Issues).