defendant is competent to participate in the adjudica-
tory process. A variety of instruments have been
developed to help structure these forensic assess-
ments; this entry describes one of the more con-
temporary competence assessment instruments, the
MacArthur Competence Assessment Tool–Criminal
Adjudication (MacCAT–CA).
In the United States, people accused of crimes have
certain rights with respect to the adjudicatory process
that are guaranteed by the Constitution. In particular,
they have the Fifth Amendment protection against
self-incrimination and rights articulated in the Sixth
Amendment, which include the assistance of legal
counsel, the right to confront their accusers, and the
right to trial by a jury of their peers.
To benefit from these rights, defendants must be
mentally competent to assert them. In Dusky v. United
States(1960), the U.S. Supreme Court articulated spe-
cific functional abilities that defendants must have to
participate competently in the adjudicatory process:
They must be able to assist counsel, and they must
have both a rational and a factual understanding of the
proceedings against them.
Most, if not all, jurisdictions recognize only mental
impairment—often characterized as “mental disease or
defect”—as a basis for incompetence to proceed to
adjudication. When questions about a defendant’s men-
tal capacities arise, the courts almost invariably solicit
the assistance of mental health professionals (primarily
psychiatrists and psychologists) in resolving the issue.
These forensic evaluators attempt to inform the court
whether, and the extent to which, the defendant’s func-
tional abilities required by Duskyare compromised by
psychiatric problems.
Historically, the primary tool available to forensic
examiners for assessing competence was the unstruc-
tured or semistructured interview. Although interview
approaches can provide valuable information, they are
vulnerable to a variety of sources of potential bias. For
example, interview-based results from evaluations of
the same defendant may be inconsistent because differ-
ent examiners (a) asked questions that varied in content
and/or difficulty, (b) had different subjective criteria for
judging the adequacy of a defendant’s responses to var-
ious questions, or (c) used different reference groups or
subjective algorithms for aggregating the information
to formulate more focused conclusions about the defen-
dant’s capacities.
The MacCAT–CA was designed to enable forensic
examiners to collect information relevant to a defendant’scompetence in a way that minimizes the influence of
clinical subjectivity. The MacCAT–CA comprises
three measures, each of which relates conceptually to
one of the Duskycriteria. Each of these measures is
described briefly below.
The Understanding measure includes 8 items that
query issues such as the general roles and responsibil-
ity of the prosecuting attorney and defense attorney,
the elements of a criminal offense, the responsibilities
of a judge and those of a jury, the nature of criminal
sentencing, and a defendant’s rights at trial. Thus, it
relates to the Duskyrequirement that a defendant have
a “factual understanding” of legal proceedings.
The Appreciation measure includes 6 items that
query the respondent about expectations regarding his
or her pending case. These items relate to issues such
as expectations about disclosing information to, and
receiving assistance from, the attorney; the likelihood
of being convicted; the likely severity of punishment if
convicted; and expectations that one will be treated
fairly by the courts. The respondent is asked to state his
or her expectations and then explain the reasons for
these beliefs. Scoring of these items involves a judg-
ment of the plausibility of the defendant’s reasons for
his or her beliefs—thus Appreciation relates to the
Duskyrequirement of a “rational understanding” of
proceedings.
Finally, the Reasoning measure includes 8 items
that require a defendant to exercise logical and rea-
soning skills in relation to legal information. Each of
5 items presents the respondent with two pieces of
hypothetical information. These pieces of information
are embedded in a hypothetical vignette (i.e., a man is
arrested after getting into a fight at a bar) and the
respondent is challenged to determine which piece of
information has the greatest legal relevance for the
hypothetical actor and to explain the basis for its
greater legal relevance. Three other Reasoning items
describe alternative dispositional choices for the
hypothetical actor, proceeding to trial or accepting a
plea agreement. The respondent’s task is to articulate
comparisons and contrasts (e.g., conduct a risks-and-
benefits analysis) between these choices, thus demon-
strating the capacity to reason about legal alternatives.
This measure is conceptually related to the Dusky
requirement of “capacity to assist counsel.”
Three structural features of the MacCAT–CA limit
the extent of interviewer subjectivity in the assessment.
First, the administration is highly structured. The
same 22 items are presented to each defendant, withMacArthur Competence Assessment Tool for Criminal Adjudication (MacCAT–CA)——— 465M-Cutler (Encyc)-45463.qxd 11/18/2007 12:43 PM Page 465