Encyclopedia of Psychology and Law

evaluations across the United States. Some jurisdictions

have augmented the Duskystandard with additional cri-

teria. In these instances, forensic psychologists may use

the ECST–R to evaluate core issues that can be supple-

mented by interview-based methods and collateral

sources.

ECST–R conclusions are based on both normative

data and case-specific deficits. Normative-based inter-

pretations compare a defendant’s ECST–R score with

that of 356 impaired but genuine pretrial defendants.

Nomothetic interpretations for competency are provided

for individual ECST–R scales based on T-score trans-

formations for moderate (60T to 69T), severe (70T to

79T), extreme (80T to 89T), and very extreme (90T and

above) elevations. Because the Supreme Court in

Daubert v. Merrell Dow Pharmaceuticals(1993) and

subsequent cases required an examination of error rates,

the ECST–R became one of the first forensic measures

to evaluate error rates in the context of standard error of

measurement. For example, at a “very probable” level of

certitude, the estimated error rate is <5.0%.

Not all competency-related abilities will be cap-

tured by the ECST–R or by any other competency

measure. Therefore, the nomothetic interpretations are

supplemented with case-specific deficits. Based on

the ECST–R and other data sources, focal deficits are

sometimes observed that are germane to competency

determinations. The ECST–R provides an opportunity

to document these case-specific deficits.

A crucial issue in competency evaluations is the gen-

uineness of the defendant’s efforts in describing his or

her psychological impairment and competency-related

abilities. Unlike alternative measures, the ECST–R pro-

vides a direct method to screen for possible malinger-

ing. If malingering is established by independent

measures such as the Structured Interview for Reported

Symptoms (SIRS), the ECST-R provides explicit guide-

lines for assessing the relationship of feigned impair-

ment to the issue of competency to stand trial.

Richard Rogers

See also Forensic Assessment; Malingering

Further Readings

Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993).

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

Rogers, R., Jackson, R. L., Sewell, K. W., & Harrison, K. S.

(2004). An examination of the ECST-R as a screen for

feigned incompetency to stand trial. Psychological

Assessment, 16,139–145.

Rogers, R., Jackson, R. L., Sewell, K. W., Tillbrook, C. E., &

Martin, M. A. (2003). Assessing dimensions of

competency to stand trial: Construct validation of the

ECST-R. Assessment, 10,344–351.

Rogers, R., & Shuman, D. W. (2005). Fundamentals of

forensic practice: Mental health and criminal law.

New York: Springer.

Rogers, R., Tillbrook, C. E., & Sewell, K. W. (2004).

Evaluation of Competency to Stand Trial-Revised

(ECST-R) and professional manual.Odessa, FL:

Psychological Assessment Resources.

EXPERTPSYCHOLOGICALTESTIMONY

Expert testimony in psychology comes in many types

and concerns a vast array of subjects. Psychological

expertise ranges widely both in scientific subject areas

and the breadth of the legal landscape covered. Indeed,

there are few, if any, legal contexts in which expert tes-

timony on psychology does not sometimes have an

impact. This is not surprising, because law shares with

psychology an abiding interest in human behavior.

Because of the large number of areas in which psy-

chology and law intersect, any summary will be some-

what incomplete. This entry, therefore, is intended to

illustrate the range of expertise and the legal contexts

in which it is put to use. It first reviews expert testi-

mony according to its subject, with sections on testi-

mony concerning past mental states, past behavior,

future behavior, and current mental states. The entry

concludes with a discussion of the probative value of

other evidence. Many of these categories of evidence

appear in both civil and criminal cases, and the basic

admissibility standards in these two legal domains are

the same. Hence, for example, predictions of future

violence might be used in civil cases (e.g., civil liabil-

ity for failing to predict violence), civil cases that are

quasi-criminal (e.g., sexually violent predator commit-

ments), and criminal cases (e.g., capital sentencing).

Also, many subjects of expert psychological testimony

are used by both prosecutors and criminal defendants

(e.g., the battered-woman syndrome [BWS]) and by

plaintiffs and civil defendants (e.g., polygraphs).

Past Mental States

In the popular imagination, the principal use of psy-

chological expertise occurs in the context of discern-

ing past mental states in criminal cases. The central

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