Confidence intervals for true scores and retest scores on clinical tests

Brophy, Alfred L.

doi:10.1002/1097-4679(198611)42:6<989::aid-jclp2270420626>3.0.co;2-q

Cited by 18 publications

(13 citation statements)

References 7 publications

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“…Essentially the judgment to be made after intervention is whether an individual's retest performance change from baseline is consistent with variation due to measurement error, or to a`real ' eå ect. A variety of methods for determining whether real change has occurred has been suggested (Brophy, 1986 ;Hsu, 1989Hsu, , 1995Jacobson & Truax, 1991 ;Nunnally & Kotsch, 1983 ;Speer, 1994 ;Speer & Greenbaum, 1995). All these techniques rely upon the calculation of a con®dence interval around the ®rst test score against which retest score can be compared.…”

Section: Discussionmentioning

confidence: 99%

Short test of semantic and phonological fluency: Normal performance, validity and test‐retest reliability

Harrison¹,

Buxton

Husain

et al. 2000

British J Clinic Psychol

189

135

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Tests of verbal fluency, whether of Semantic Fluency (SF) or Phonological Fluency (PF), are often used as a standard method of neuropsychological assessment. However, very little normative data, standardized on a UK sample, is available, and little is known about the utility of popularly used 'short-forms' of these tasks. Additionally, very little is known about verbal fluency test-retest reliability. In this report we describe the performance of N = 365 normal participants on a version of SF requiring the generation of exemplars of the category 'animals' and a version of the PF task requiring participants to generate words beginning with the letter 'B'. From this data we have derived a percentile distribution for both tasks. We also addressed the impact of sex, age, years of education and IQ upon both SF and PF performance. No sex differences were found on either the PF or the SF tasks. A significant but small correlation between age and SF, but not PF, was observed. Modest correlations between both years of education and IQ and PF and SF performance were also seen. We also report test-retest reliability scores for performance on both SF and PF tasks. Performance on the longer 'FAS' version was found to correlate highly with scores obtained using just the letter 'B'. This suggests that little additional advantage obtains from administering three-letter versions of PF. An extremely high degree of correlation between SF tasks in which participants are given 1 minute and scores obtained when participants are given 1 minute 30 seconds was also observed. Finally, in order to assist users in deciding whether a changed retest score is due to error measurement or a real effect, we calculated Standard Error of Prediction (SEP) scores.

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Section: Discussionmentioning

confidence: 99%

Short test of semantic and phonological fluency: Normal performance, validity and test‐retest reliability

Harrison¹,

Buxton

Husain

et al. 2000

British J Clinic Psychol

189

135

View full text Add to dashboard Cite

show abstract

“…Reliabilities for the Verbal, Performance, and Full Scales were determined using the subtest intercorrelation matrix (see Table l), the obtained subtest reliabilities, and formulae provided by Silverstein (1990). Standard errors of measure (SEM) and estimation (SEMc) then were calculated for each subtest and scale score (Brophy, 1986;Kramer, 1990). Comparisons were conducted to determine the significance of the differences between obtained subtest reliabilities for the psychiatric inpatient sample and those reported for the 25-to 34-year-old portion of the standardization group (Wechsler, 1981).…”

Section: Methodsmentioning

confidence: 99%

Reliability of the WAIS-R with psychiatric inpatients

Boone

1992

J. Clin. Psychol.

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WAIS‐R subtest and composite scale reliabilities, standard errors of measurement, and standard errors of estimate were determined for a sample of psychiatric inpatients (N = 100). For Digit Span and Digit Symbol, test‐ retest stability coefficients were obtained; split‐half reliability coefficients were calculated for all other subtests. With the exception of Object Assembly (rxx =.38), all subtest and composite scale reliability coefficients were large and acceptable. Based on the standard error of measure, the most reliable WAIS‐R subtests were Digit Symbol (.77), Information (1.04), and Picture Completion (1.07). Reliability coefficients for the psychiatric inpatient sample were, in general, comparable to those values reported for the standardization group (Wechsler, 1981). Significant differences were obtained only on the Object Assembly and Vocabulary subtests.

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“…/•", values were extracted from Wechsler's (198 1) Table 10, r# values from Table 1 5. Standard errors of measurement can take three forms, as outlined by Dudek (1979) and Lord and Novick (1968) in the general context, and by Brophy (1986) and Knight (1983) in relation to the WAIS-R. The two standard errors of interest here are the standard errors of estimation (SE E ) and prediction (5£,).…”

Section: Dq=mentioning

confidence: 99%

Some tables for statistically based interpretation of WAIS—R factor scores.

Atkinson¹

1991

Psychological Assessment: A Journal of Consulting and Clinical

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If we are to make clinical use of the findings regarding the Wechsler Adult Intelligence Scale-Revised (WAIS-R) factor structure, then we need information analogous to that available for Full Scale, Verbal, and Performance IQs. This article provides tables for determining (a) confidence intervals around an examinee's Verbal Comprehension, Perceptual Organization, and Memory/ Freedom From Distractibility deviation quotients (DQs); (b) the probability that variation in DQs across administrations reflects real change, rather than measurement error; (c) the difference between DQs necessary for statistical significance; and (e) the abnormality of differences between DQs. All statistics were derived from data provided in the WAIS-R manual.The factor structure of Wechsler's intelligence scales has proven to be of clinical (Kaufman, 1979) and theoretical (Hill, Reddon, & Jackson, 1985) importance. Great effort has been invested in extracting and confirming its makeup and exploring its correlates. Hill et al. reviewed over 70 studies of Wechsler factor structure, dating back to 1941. Atkinson et al. (1990) reviewed over 20 factor-analytic investigations of the Wechsler Adult Intelligence Scale-Revised (WAIS-R; Wechsler, 1981) alone. They concluded that WAIS-R factor structure was robust across samples, tests, statistical analyses, and time. Downgrading its measurement scales and distorting its distribution had little effect on WAIS-R factor structure. Atkinson et al. suggested that these findings supported (a) the predictive clinical use of factor scores and (b) theoretical assumptions about factor scores as reflective of stable, latent abilities.However, if we are to make practical use of these findings to interpret examinees' factor scores, then we need information comparable to that provided for interpretation of WAIS-R Full Scale, Verbal, and Performance IQs. Necessary information includes reliability coefficients, as offered for the aforementioned IQs by Wechsler (1981); difference scores required for statistical significance, as provided for Verbal IQ-Performance IQ discrepancies by Naglieri (1982); and standard errors of estimation and prediction as well as data on the abnormality of differences between scores, as provided for IQ scores by Knight (1983). This article supplies the requisite tables for factor score interpretation. The figures on them were derived from data provided in the WAIS-R manual, and their clinical application is valid only to the extent that an individual examinee is represented by the standardization sample. Method and ResultsFor computational purposes, the three WAIS-R factors-Verbal Comprehension (VC), Perceptual Organization (PO), and Memory/ Correspondence concerning this article should be addressed to Leslie Atkinson,

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Confidence intervals for true scores and retest scores on clinical tests

Cited by 18 publications

References 7 publications

Short test of semantic and phonological fluency: Normal performance, validity and test‐retest reliability

Short test of semantic and phonological fluency: Normal performance, validity and test‐retest reliability

Reliability of the WAIS-R with psychiatric inpatients

Some tables for statistically based interpretation of WAIS—R factor scores.

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