Encyclopedia of Psychology and Law

instructions for both initial presentation and follow-up

queries/probes to minimize examiner-related differ-

ences in the presentation. Second, explicit instructions

and criteria are written for scoring each item, which

minimizes differences in examiners’ judgment as to

what is a correct or incorrect answer. Third, the total

score for each measure (sum of item scores for

Understanding, Reasoning, and Appreciation) is inter-

preted in light of norms based on a large, multistate

sample of offenders recruited in jails and forensic psy-

chiatric hospitals. Thus, statistical norms exist to guide

clinical interpretation as to whether, and to what extent,

a particular respondent manifests impairment in the

functional legal abilities articulated in Dusky.

Research with adult offenders has demonstrated

that the MacCAT–CA measures are reliable, with

internal consistency estimates (Cronbach’s alpha) of

.85, .81, and .88 for Understanding, Reasoning, and

Appreciation, respectively. Interscorer reliability of

.90, .85, and .75 for Understanding, Reasoning, and

Appreciation, respectively, were reported in the

MacCAT–CA manual. Evidence for the validity of the

instrument includes that each measure correlates in

expected ways with measures of intellectual capacity

(positively) and with measures of psychotic sympto-

matology (negatively). Furthermore, poorer scores are

obtained on MacCAT–CA measures by defendants

who have been adjudicated incompetent to stand trial

than by comparison groups of jail inmates awaiting

trial. Finally, MacCAT–CA scores help to discrimi-

nate competent from incompetent defendants after

controlling for measures of other constructs including

demographic features, criminal history, and psy-

chopathology variables.

Although the MacCAT–CA offers some advantages

in terms of structuring and standardizing certain com-

petence-related inquiries, it was designed to supple-

ment, rather than to replace, the clinical interview in

assessing adjudicative competence. It does not assess

directly all the factors that might affect a defendant’s

competence—for example, poor memory for events at

or near the time of the alleged crime or incoherence of

thoughts or speech that might make assisting counsel

difficult. Furthermore, the clinician using the

MacCAT–CA must still make judgments regarding

symptoms of mental disorder and their contribution, if

any, to poor performance on the MacCAT–CA. Thus,

the MacCAT–CA is not a stand-alone measure of com-

petence. It is best conceived as its name indicates—

a “tool” to assist mental health professionals in

their assessment of defendants’ competence-related

abilities.

Norman G. Poythress

See alsoAdjudicative Competence of Youth; Competency,

Foundational and Decisional; Competency Assessment

Instrument (CAI); Forensic Assessment

Further Readings

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

Otto, R. K., Poythress, N. G., Nicholson, R. A., Edens, J. F.,

Monahan, J., Bonnie, R. J., et al. (1998). Psychometric

properties of the MacArthur Competence Assessment

Tool–Criminal Adjudication (MacCAT–CA).

Psychological Assessment, 10,435–443.

Poythress, N. G., Bonnie, R. J., Monahan, J., Otto, R., &

Hoge, S. K. (2002). Adjudicative competence: The

MacArthur studies.New York: Kluwer/Plenum.

Stafford, K. P. (2002). Assessment of competence to stand trial.

In A. M. Goldstein (Ed.),Handbook of psychology: Vol. 11.

Forensic psychology (pp. 359–380). Hoboken, NJ: Wiley.

MACARTHUR COMPETENCE

ASSESSMENTTOOL FOR

TREATMENT(MACCAT–T)

The MacArthur Competence Assessment Tool for

Treatment (MacCAT–T) is an instrument designed to

assess decision-making capacity. Designed as part of

the MacArthur Competence Treatment Competence

Study, a multiyear, multisite effort named for the well-

known philanthropic foundation, the tool operational-

izes established elements of competent decisions. The

semistructured instrument, which can be completed

within 20 to 30 minutes, guides clinicians through the

discussion of a specific treatment decision and scores

responses on four separate scales.

Structured disclosures assess patients’ understand-

ing, reasoning, appreciation, and choice, the four ele-

ments of decision making established in reviews of

the established legal and ethical literature. For under-

standing, patients are tested on their comprehension

of the nature of their illness, recommended treatment,

alternatives, and risks and benefits. Reasoning evalu-

ates patients’ problem-solving ability when faced with

a specific treatment choice. Appreciation assesses

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