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Biomedical subjects

R I Frederick

Publications and source records attributed to R I Frederick.

6 recordsLinked to original sources
PubMed2001

The relationship between criminal charges, diagnoses, and psycholegal opinions among federal pretrial defendants.

This study analyzed data from 1710 criminal defendants referred by federal courts throughout the United States. We examined 12 categories of criminal charges with respect to diagnosed psychopathology and opinions related to competence to stand trial (CST) and criminal responsibility (CR) at the time of the alleged offense. Overall, 18% of the present sample were found to be incompetent to stand trial, while 12% were found to be not criminally responsible or 'insane.' In this study, crimes were associated with rates of psychopathology and rates of opinions regarding CST and CR. The findings of this study suggest that individuals who are charged with different crimes have different mental states and psychopathology and are therefore found to have differential rates of competence and sanity.

Adult↗
PubMed2000

Mixed group validation: a method to address the limitations of criterion group validation in research on malingering detection.

Mixed group validation (MGV) is offered as an alternative to criterion group validation (CGV) to estimate the true positive and false positive rates of tests and other diagnostic signs. CGV requires perfect confidence about each research participant's status with respect to the presence or absence of pathology. MGV determines diagnostic efficiencies based on group data; knowing an individual's status with respect to pathology is not required. MGV can use relatively weak indicators to validate better diagnostic signs, whereas CGV requires perfect diagnostic signs to avoid error in computing true positive and false positive rates. The process of MGV is explained, and a computer simulation demonstrates the soundness of the procedure. MGV of the Rey 15-Item Memory Test (Rey, 1958) for 723 pre-trial criminal defendants resulted in higher estimates of true positive rates and lower estimates of false positive rates as compared with prior research conducted with CGV. The author demonstrates how MGV addresses all the criticisms Rogers (1997b) outlined for differential prevalence designs in malingering detection research.

Adolescent↗
PubMed2000

Development and validation of the Validity Indicator Profile.

The Validity Indicator Profile (VIP; Frederick, 1997) is a two-alternative forced choice (2AFC) procedure intended to identify when the results of cognitive and neuropsychological testing may be invalid because of malingering or other problematic response styles. The test consists of 100 problems that assess nonverbal abstraction capacity and 78 word-definition problems. The VIP attempts to establish whether an individual's performance in an assessment battery should be considered representative of his or her true overall capacities (valid or invalid). Performances classified as valid are classified as "compliant" and reflect a high effort to respond correctly. Performances classified as invalid are subclassified as "careless" (low effort to respond correctly), "irrelevant" (low effort to respond incorrectly), or "malingering" (high effort to respond incorrectly). The VIP development sample included 944 nonclinical participants and 104 adults undergoing neuropsychological evaluation. The cross-validation sample consisted of 152 nonclinical participants, 61 brain-injured adults, 49 individuals considered to be at risk for malingering, and 100 randomly generated VIP protocols. The nonverbal subtest of the VIP demonstrated an overall classification rate of 79.8%, with 73.5% sensitivity and 85.7% specificity. The verbal subtest of the VIP demonstrated an overall classification rate of 75.5%, with 67.3% sensitivity and 83.1% specificity.

Adolescent↗
PubMed2000

A personal floor effect strategy to evaluate the validity of performance on memory tests.

Four methods of assessing the validity of performance on a word recognition test were compared among 609 criminal defendants engaged in competency-to-stand-trial evaluations. One of the methods, the "normative" floor effect strategy, involves comparing an individual's performance to the average performance of individuals with true memory impairment. In this sample, 16.9% of defendants performed below the normative floor for individuals with true impairment. Another method, the "personal" floor effect strategy, identifies performance as suspect when individuals perform below a level for which they themselves have already demonstrated intact ability. In this sample, the personal floor effect strategy identified fewer instances of suspicious performance (15.6%), but the strategy may be less sensitive to true memory impairment than the normative floor effect. Consequently, the personal floor effect strategy may be more compelling as evidence of poor effort or bad intentions on memory testing. Convergent validity of the personal floor effect strategy is demonstrated over four analyses.

Adolescent↗
PubMed1995

Adapting symptom validity testing to evaluate suspicious complaints of amnesia in medicolegal evaluations.

Symptom validity testing was adapted to assess suspicious complaints of amnesia. In the adaptation, two-alternative, forced-choice memory questions were generated for subject matter claimed to be forgotten. The number of questions correctly answered was then compared to the expected number of questions to be correctly answered if no knowledge actually existed. Three case studies are presented, two of competency-to-stand-trial evaluees and one of an insurance medical examinee. In each case, the use of this procedure generated the conclusion that the knowledge claimed to be forgotten was actually remembered; however, not all individuals were classified as malingerers.

Accidents, Traffic↗