Encyclopedia of Psychology and Law

alter their performance when asked to do poorly.

These individuals scored lower than a group of defen-

dants with mental retardation who had been evaluated

as incompetent to stand trial and the control group of

defendants with mental retardation who took the test

under standard conditions. This reaffirms the need to

supplement scores with additional information.

Appropriate Use of the CAST*MR

It is important that competency evaluations of persons

with mental retardation include multiple sources of

information. A single test score should not be the sole

determinant of defendant competency. An evaluation

test battery for persons with mental retardation should

include an individually administered global test of

intelligence and assessments of expressive and recep-

tive language, academic skills, and adaptive behavior.

Social history provides additional information on cog-

nitive and academic skills and previous diagnoses.

Interviews with key individuals who have known the

defendant over time provides information relevant to

competency, such as the defendant’s problem-solving

and decision-making skills. These sources provide

corroborative information that can assist in the inter-

pretation of CAST*MR results.

Finally, CAST*MR results should be supported

with additional information on the defendant’s psy-

cholegal abilities. Other sources include information

gained through questioning in the clinical interview and

can include an additional assessment of competence to

stand trial. It is important to check for understanding by

having the defendant explain concepts in his or her own

words. Decisional competency is a critical area for indi-

viduals with mental retardation. It is important to query

the individual on his or her understanding of the

defense strategy and his or her legal options.

The CAST*MR is published by IDS in Columbus,

Ohio, and is used by evaluators throughout the United

States.

Caroline Everington and Ruth Luckasson

See also Competency, Foundational and Decisional;

Competency to Stand Trial; Mental Retardation and the

Death Penalty

Further Readings

Dusky v. United States,362 U.S. 402 (1960).

Everington, C., DeBerge, K., & Mauer, D. (2001). The

relationship between language skills and competence to

stand trial abilities in persons with mental retardation.

Journal of Psychiatry and Law, 28,475–492.

Everington, C., & Dunn, C. (1995). A second validation

study of the competence assessment for standing trial for

defendants with mental retardation. Criminal Justice and

Behavior, 22,44–59.

Everington, C., & Luckasson, R. (1992). The competence

assessment for standing trial for defendants with mental

retardation (CAST*MR). Worthington, OH: IDS.

Everington, C., Notario-Smull, H., & Horton, M. (in press).

Can defendants with mental retardation successfully fake

their performance on a test of competence to stand trial?

Behavioral Sciences and the Law.

COMPETENCY, FOUNDATIONAL

AND DECISIONAL

The law in the United States requires that criminal

defendants be competent to participate in the adjudica-

tory proceedings against them. Legal competence is a

complex construct that includes both the fundamental

capacities needed to participate in the process (adju-

dicative competence) and a degree of autonomy in

making important case decisions (decisional compe-

tence). This entry examines the legal criteria for com-

petence as well as the societal values that underlie the

requirements concerning the ability of those accused

of crime to participate in proceedings against them.

Criteria for Adjudicative Competence

In the United States, individuals accused of crimes are

afforded certain constitutional rights and protections dur-

ing the adjudicatory process. The Fifth Amendment, for

example, protects defendants from being compelled by

the state to testify against themselves. The Sixth

Amendment provides defendants with the right to the

assistance of legal counsel, the right to confront their

accusers and the evidence against them, and the right to

a trial by jury. To benefit from these rights, defendants

must be mentally able to assert them. It is not enough that

defendants be physically present during adjudicatory

proceedings; they must also have the mental capacity to

exercise their rights—that is, they must be “competent.”

When questions are raised about a defendant’s

competence, it is the responsibility of the trial judge to

make an inquiry and determine whether he or she has

the requisite abilities to go forward to adjudication.

The broad criteria for adjudicative competence were

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