Competency evaluation and assessment instruments

DEFINITION: Psychological evaluation instruments that assess the ability of persons to function meaningfully and knowingly, without serious deficiencies, in understanding legal proceedings, communicating with attorneys, understanding their roles in proceedings, and making legally relevant decisions.

SIGNIFICANCE: Legal competency is the capacity to understand the nature and purposes of legal rights, obligations, and proceedings. Forensic psychiatrists are often involved in conducting competency evaluations, which assist in protecting the rights of those being evaluated by determining the subjects’ competency to stand trial.

In 1960, the US Supreme Court established a standard called the Dusky Standard based on an appeal filed by a man named Milton Dusky, who was diagnosed with schizophrenia, after he received a forty-five-year jail sentence for kidnapping and assisting two teenagers in carrying out the rape of a sixteen-year-old girl. In its decision in Dusky v. United States, the Court ruled that to be deemed competent to stand trial, individuals must have a minimum level of understanding of the legal proceedings and the ability to assist their attorneys in their own defense. As a result, at the retrial, Dusky’s sentence was reduced to twenty years.

The perception of competency is related to a defendant’s ability to understand charges, relevant facts, legal issues and procedures, potential legal defenses, and possible dispositions, pleas, and penalties as well as the roles of the lawyers, judge, jury, witnesses, and defendant. Also important are the individual’s abilities to identify witnesses, to communicate rationally with counsel, to comprehend instructions and advice, to make decisions, to help plan legal strategy, to follow testimony for contradictions or errors, to testify and be cross-examined, to challenge prosecution witnesses, to tolerate stress at trial and while awaiting trial, to refrain from irrational behavior during trial, to disclose pertinent facts surrounding alleged offenses, and to use available legal safeguards.

Aside from competency, two other areas of defense are related to mental capacity: diminished capacity and mitigating circumstances. Diminished capacity evaluations focus on the ability of defendants to intend to commit the crimes of which they are accused. Evaluations of mitigating circumstances focus on factors that limit the severity of or the defendants’ culpability for an action, enough to consider reducing the extent of the damages or punishment but not excuse the conduct.

Evaluation Process

An evaluation of a defendant’s competency to stand trial can be ordered by the defense, the prosecution, or the judge. Competency to stand trial involves the defendant’s ability to understand the legal proceedings, the charges, the roles of court personnel, the difference between pleas of guilty and not guilty, and the meaning of a plea bargain. It also encompasses the defendant’s ability to assist in his or her defense, to work with the attorney, and to take an active part in the defense.

A psychological evaluation of an individual’s competency to stand trial includes a review of the person’s medical and psychological histories as provided by the individual being evaluated as well as by that person’s family members. Assessment for brain damage caused by head injuries, dementias, and acute or chronic alcohol and drug abuse may also be included. A clinical interview follows and includes assessments regarding orientation, short-term memory, and ability to reason. After the clinical interview, psychological testing is performed based on the results of the interview.

In criminal court, a defendant must be competent to waive Miranda rights if a confession is being used, to stand trial, to be sentenced, and to serve a sentence if found guilty. Additionally, the defendant must have been competent at the time of the offense and must be competent to be executed if a death penalty is ruled. Individual competency determinations do not automatically lead to determinations of competency in other areas. For example, competency at the time of the offense does not guarantee that the defendant will be competent to stand trial later. The courts can dismiss charges against individuals if there is no indication that competency will return following treatment.

Competencies to waive constitutional rights and to waive the right to counsel are addressed in the evaluator’s report on competency to stand trial. Such a report includes the following elements: information regarding the source of the referral; date, place, and time of evaluation; non-confidentiality statement; references and interviews used to prepare the report; criteria for competency to stand trial; background information on the defendant; information on the defendant’s history of psychiatric and medical treatment and substance abuse; results of the mental status exam; the evaluator’s findings on the defendant’s level of mental function and ability to understand the proceedings; and statements from the defendant that demonstrate the defendant’s understanding of the issues of the case (charges, legal situation, roles of courtroom personnel, differences between pleas, and range of possible verdicts). The report also assesses the defendant’s ability to assist in the defense (based on the defendant’s ability to recount his or her whereabouts and activities at the time of the offense) and to interact with the defense attorney and behave in an acceptable manner in the courtroom. Some reasons that defendants are deemed incompetent to stand trial are low intelligence, dementia, depression, mania, and paranoid delusions. The following government entities play different roles in evaluating an individual’s competency to stand trial: behavioral health, courts and court-appointed alienists and staff, district attorneys, public defenders, sheriffs, probation, and department state hospitals.

Assessment Instruments

Many psychological tests have been developed for use in evaluating mental competency. Among those most frequently employed by forensic psychiatrists are the Competency Screening Test, the Competency Assessment Instrument, the Interdisciplinary Fitness Interview, and the Georgia Court Competency Test.

The long form of the Competency Screening Test (CST), developed by a group of Harvard psychologists, comprises twenty-two sentence stems concerning hypothetical legal situations; the person being evaluated is asked to complete each sentence. An example item is “When I go to court, the lawyer will ______.” The evaluator scores each answer as indicating competency, questionable competency, or incompetency. A short form of the CST is also sometimes used; the short form comprises just five sentence stems.

The Competency Assessment Instrument (CAI), developed by the same group of psychologists who created the CST, requires a one-hour structured clinical interview that explores the thoughts and feelings of the person being evaluated in thirteen topic areas, including coping with stress and sense of optimism as well as an understanding of legal proceedings. The CAI provides sample questions for each topic area, and the evaluator scores the responses of the person being evaluated using a five-point scale of competency.

The Interdisciplinary Fitness Interview (IFI) is administered jointly by a mental health professional and an attorney. The IFI, which takes thirty minutes, addresses both legal and mental health issues, with greater focus on mental illness than some other instruments.

The Georgia Court Competency Test (GCCT) consists of twenty-one questions related to the client’s general legal knowledge and knowledge of such specifics as the judge’s job and the lawyers’ job. This tool is particularly useful for measuring behavioral aspects of competency.

The MacArthur Competence Assessment Tool-Criminal Adjudication, which has been studied and evaluated for validity, includes twenty-two items examining three abilities: understanding, reasoning, and appreciation. Other competency tests that have shown promise include the Computer-Assisted Determination of Competence to Proceed, among others.

Bibliography

Bardwell, Mark C., and Bruce A. Arrigo. Criminal Competency on Trial: The Case of Colin Ferguson. Carolina Academic Press, 2002.

Bartlett, M. “Introducing the BCAT: A Tool to Aid Treatment Providers in Assessing Adjudicative Competence.” Journal of Forensic Social Work, vol. 7, no. 1, 2023, pp. 14–31, doi:10.15763/issn.1936-9298.2023.7.1.14-31. Accessed 5 Dec. 2025.

California State Association of Counties. “Issue Brief: Incompetent to Stand Trial.” CSAC Legislative Briefs, 2025, www.counties.org/wp-content/uploads/2025/04/incompetent_to_stand_trial_issue_brief.pdf. Accessed 5 Dec. 2025.

Dagher-Margosian, Jeanice. “Representing the Cognitively Disabled Client in a Criminal Case.” Disabilities Project Newsletter (State Bar of Michigan), vol. 2, Mar. 2006.

Grisso, Thomas. Evaluating Competencies: Forensic Assessments and Instruments. 2nd ed., Springer, 2002.

Martins, Mariana Veloso, et al. “Evaluation of Assessment Instruments for Working Alliance in Psychological Interventions with Adolescents: A Systematic Review.” Clinical Psychology Review, vol. 119, July 2025, doi:10.1016/j.cpr.2025.102586. Accessed 5 Dec. 2025.

Resnick, Phillip J., and Stephen Noffsinger. “Competency to Stand Trial and the Insanity Defense.” Textbook of Forensic Psychiatry, edited by Robert I. Simon and Liza H. Gold. American Psychiatric Publishing, 2003.

Rogers, Richard, and Daniel W. Shuman. Fundamentals of Criminal Practice: Mental Health and Criminal Law. Springer, 2005.

Swerdlow-Freed, Daniel H. “Assessment of Competency to Stand Trial and Criminal Responsibility.” Michigan Criminal Law Annual Journal, 2003.