Evaluation of Competence to Stand Trial

Evaluation of Competency to Stand Trial-Revised (ECST-R) is a semistructured interview that is designed to assess criminal defendants’ capacities as they relate to courtroom proceedings. In Dusky v. United States (1960), the U.S. Supreme Court established the three basic prongs required for competency to stand trial: (1) factual understanding of the proceedings, (2) rational understanding of the proceedings, and (3) rational ability to consult with counsel. The ECST-R was developed and validated for assessment of the Dusky prongs. In addition, the ECST-R includes a specific screen for feigned incompetency.

ECST-R Description and Development

Prototypical analysis with competency experts identified core representative items for three ECST-R competency scales: Factual Understanding of the Courtroom Proceedings (FAC), Rational Understanding of the Courtroom Proceedings (RAC), and Consult with Counsel (CWC). Prototypical items were also evaluated by trial judges and highly experienced forensic psychiatrists. In addition to competency scales, the ECST-R uses multiple detection strategies for validating its four Atypical Presentation (ATP) Scales: Psychotic (ATP-P), Nonpsychotic (ATP-N), Both (ATP-B; sum of ATP-P and ATP-N), and Impairment (ATP-I). A fifth ATP scale is not used to assess feigning, but masks the intent of the other ATP scales: Realistic (ATP-R).

Samples from four major studies were combined for normative data and test validation. Three samples consisted of mentally disordered offenders: (1) 100 detainees on a psychiatric unit of a large metropolitan jail, (2) competency cases including 28 pretrial evaluations and 42 inpatients in competency restoration, and (3) 56 inpatients in competency restoration. They were supplemented with 95 jail inmates and 89 additional competency referrals.

ECST-R Reliability

Internal consistencies (alpha coefficients) were high for overall competency (.93) and the individual competency scales: FAC (.87), RAC (.89), and CWC (.83). Interrater reliabilities were exceptional for these competency scales: FAC (.96), RAC (.91), and CWC (.91). Even when focusing on individual competency items, interrater reliabilities remained strong (Mr = .77). In addition, most individual competency ratings remained stable across a 1-week interval with more than 90% of the ratings remaining identical. ATP scales had moderate to high internal consistencies (alphas from .70 to .87) with the exception of ATP-R (.63), which serves a different purpose. ATP scales have outstanding inter-rater reliabilities (rs from .98 to 1.00)

ECST-R Validity

The previously described prototypical analysis provided strong evidence of content validity. For construct validity, confirmatory factor analyses were used to test various models of the Dusky prongs for the ECST-R competency items. With one cross-loading, the confirmatory factor analyses confirmed a three-factor model with high loadings (M = .72) for competency items on their designated scales.

For criterion-related validity, ECST-R competency scales demonstrated a high concordance with independent opinions of experienced forensic experts and legal outcomes. It also evidenced moderate correlations with the MacCAT-CA, despite major conceptual differences between the two competency measures. In addition, very large effect sizes were found between defendants with and without impairment on ECST-R competency scales for both the severity of psychotic symptoms (Cohen’s ds from 1.95 to 2.98) and overall functioning (ds from 1.60 to 1.75).

The ATP scales were validated using a combination of known-group comparisons and simulation designs. Both suspected malingerers and simulators produced much higher scores than genuine inpatients on the ATP scales with the logical exception of ATP-R. Very large effect sizes were found for both suspected malingerers (Md = 1.99) and simulators (Md = 1.74).

ECST-R Forensic Applications

The ECST-R is a second-generation competency measure that was carefully constructed and validated to evaluate the Dusky prongs, which applies to competency evaluations across the United States. Some jurisdictions have augmented the Dusky standard with additional criteria. In these instances, forensic psychologists may use the ECST-R to evaluate core issues that can be supplemented by interview-based methods and collateral sources.

ECST-R conclusions are based on both normative data and case-specific deficits. Normative-based interpretations 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 transformations 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 captured 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 genuineness of the defendant’s efforts in describing his or her psychological impairment and competency-related abilities. Unlike alternative measures, the ECST-R provides a direct method to screen for possible malingering. If malingering is established by independent measures such as the Structured Interview for Reported Symptoms (SIRS), the ECST-R provides explicit guidelines for assessing the relationship of feigned impairment to the issue of competency to stand trial.

References:

  1. Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993).
  2. Dusky v. United States, 362 U.S. 402 (1960).
  3. 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.
  4. 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.
  5. Rogers, R., & Shuman, D. W. (2005). Fundamentals of forensic practice: Mental health and criminal law. New York: Springer.
  6. 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.

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