FASS key terms

A judge's gatekeeping test for admitting expert testimony, weighing whether the method is testable, peer reviewed, has a known error rate, and is generally accepted in its field.

An older admissibility rule holding that expert scientific testimony must be based on methods generally accepted by the relevant scientific community before a court will allow it.

A person with specialized knowledge who may offer opinions to a court to help the fact finder understand evidence beyond ordinary lay understanding, subject to qualification by the judge.

A defendant's present ability to understand the proceedings and to assist counsel in their own defense, evaluated at the time of trial rather than at the time of the alleged offense.

A legal excuse from criminal responsibility for defendants who, because of severe mental disorder at the time of the offense, lacked the capacity to know wrongfulness or to conform conduct to law.

The mental state element of a crime, such as intent, knowledge, recklessness, or negligence, that the prosecution must prove alongside the prohibited act.

The physical or external element of a crime, meaning the prohibited act or omission that the law defines as criminal, apart from the person's mental state.

The intentional production or exaggeration of symptoms for an external incentive such as avoiding prosecution, obtaining compensation, or securing medication, distinguished from genuine disorder.

Deliberate fabrication or simulation of psychological or physical symptoms, which may or may not serve an obvious external goal and must be assessed with validated effort measures.

A structured measure, often forced-choice or embedded in a battery, designed to detect exaggerated, inconsistent, or improbable responding rather than to assess the severity of genuine symptoms.

A structured process of estimating the likelihood that a person will commit violence or reoffend, combining actuarial tools, clinical judgment, and information about historical and situational factors.

A risk estimate produced by mechanically combining fixed risk items using an empirically derived formula, yielding a probability or score rather than a narrative clinical opinion.

A risk assessment approach in which clinicians rate a defined set of empirically supported risk factors and then exercise judgment to reach a final formulation and management plan.

Characteristics or circumstances, such as stable employment, social support, or treatment engagement, that reduce the likelihood of violence or reoffending and inform risk management planning.

The proportion of people in a defined population who show a given outcome, such as violence or reoffending, over a specified period, which strongly shapes predictive accuracy.

The proportion of people who truly have a condition or outcome who are correctly identified by a test or instrument as having it, also called the true positive rate.

The proportion of people who truly do not have a condition who are correctly identified by a test or instrument as not having it, also called the true negative rate.

The probability that a person flagged as positive by a test actually has the condition, which depends on both test accuracy and the prevalence of the condition in the population.

The legal ability to make a valid will, generally requiring that the person know the nature and extent of their property and the natural objects of their bounty at the time of signing.

A court-ordered arrangement in which a person or agency is appointed to make personal or financial decisions for someone judged unable to manage their own affairs.

Agreement to evaluation or treatment given after the person understands the purpose, procedures, risks, benefits, alternatives, and limits of confidentiality, and voluntarily chooses to participate.

The ethical and often legal duty of a professional not to disclose information learned in a professional relationship without proper authorization or a recognized legal exception.

A legal right held by a client or patient to prevent disclosure of protected communications in legal proceedings, which can be waived and is narrower than the ethical duty of confidentiality.

A legal or ethical obligation, arising in some jurisdictions when a client poses serious danger to an identifiable person, to take reasonable steps such as warning or notifying authorities.

An evaluation conducted for a legal purpose, addressing a specific psycholegal question, with methods selected for relevance to that question and results communicated to a legal decision maker.

A personality construct marked by affective and interpersonal deficits such as callousness, manipulativeness, and shallow affect, plus impulsive and antisocial behavior, measured by structured instruments.

A persistent pattern of disregard for and violation of the rights of others, beginning in childhood or adolescence and continuing into adulthood, diagnosed from behavioral criteria.

A childhood or adolescent pattern of behavior violating the rights of others or major age-appropriate norms, including aggression, property destruction, deceitfulness, and serious rule violations.

The consistency of scores across items, occasions, or raters, often estimated by internal consistency, test-retest, or interrater coefficients, and a precondition for valid interpretation.

The degree to which a test or assessment measures what it is intended to measure and supports the specific inferences drawn from scores in a given context.

An index of the average amount of error in an individual's observed score, used to build confidence intervals around a score rather than treating it as exact.

Involuntary hospitalization ordered by a court for a person with mental disorder who meets statutory criteria, typically serious risk of harm to self or others or grave disability.

A patient's capacity to understand relevant information, appreciate the consequences of choices, reason about alternatives, and express a choice regarding proposed medical or psychiatric treatment.

A collaborative professional service in which a psychologist advises another party, such as a court, agency, or treatment team, without necessarily assuming responsibility for the case.

Sworn out-of-court testimony recorded before trial, used to discover an opposing expert's opinions, methods, and basis, and potentially to impeach testimony later.

A framework examining how legal rules, procedures, and roles affect the psychological well-being of people involved, and using that knowledge to shape law and court practice.

A specialized court, such as drug or mental health court, that uses judicial supervision and treatment linkages to address the underlying problems contributing to justice involvement.