Showing papers on "Intraclass correlation published in 1988"
TL;DR: An estimate is obtained of the standard error for the corrected correlation coefficient and an associated 100% x (1-alpha) confidence interval which is useful in hypothesis testing for comparisons of correlation coefficients based on data with different degrees of random error.
Abstract: It is well known that random measurement error can attenuate the correlation coefficient between two variables. One possible solution to this problem is to estimate the correlation coefficient based on an average of a large number of replicates for each individual. As an alternative, several authors have proposed an unattenuated (or corrected) correlation coefficient which is an estimate of the true correlation between two variables after removing the effect of random measurement error. In this paper, the authors obtain an estimate of the standard error for the corrected correlation coefficient and an associated 100% x (1-alpha) confidence interval. The standard error takes into account the variability of the observed correlation coefficient as well as the estimated intraclass correlation coefficient between replicates for one or both variables. The standard error is useful in hypothesis testing for comparisons of correlation coefficients based on data with different degrees of random error. In addition, the standard error can be used to evaluate the relative efficiency of different study designs. Specifically, an investigator often has the option of obtaining either a few replicates on a large number of individuals, or many replicates on a small number of individuals. If one establishes the criterion of minimizing the standard error of the corrected coefficient while fixing the total number of measurements obtained, in almost all instances it is optimal to obtain no more than five replicates per individual. If the intraclass correlation is greater than or equal to 0.5, it is usually optimal to obtain no more than two replicates per individual.
286 citations
TL;DR: Compared with a manual goniometer, the added costs for purchase and use of the Orthoranger appear to be unnecessary until such time that factors enhancing its inherent reliability are identified.
Abstract: The purposes of this study were to determine 1) the reliability of the Orthoranger for assessing active lower extremity joint range of motion, 2) specific methods for applying the Orthoranger, and 3) whether a correlation exists between the measurements obtained with the Orthoranger and those obtained with a standard goniometer Ten men and 10 women, mean ages 283 ± 51 and 300 ± 101 years, respectively, participated in the study Random selection was used to determine testing sequences The Orthoranger and the goniometer were used to measure each joint three times during the five sessions Results indicated that both instruments were reliable for assessing active lower extremity joint ROM The goniometer showed greater intraclass correlations and confidence levels for all movements except hip lateral rotation, which demonstrated a higher intraclass correlation for the Orthoranger In addition, all motions except hip adduction and knee extension demonstrated a positive relationship between instruments Compared with a manual goniometer, the added costs for purchase and use of the Orthoranger appear to be unnecessary until such time that factors enhancing its inherent reliability are identified
119 citations
TL;DR: In this article, the authors show that l'approximation suggeree par Hill et Smith (1977) for variance asymptotique is in general inadequate.
Abstract: On obtient des resultats asymptotiques qui permettent de demontrer que l'approximation suggeree par Hill et Smith (1977) pour la variance asymptotique est en general inadequate
81 citations
TL;DR: Using a variant of the intraclass correlation coefficient (ICC), this program computes the reliability of dimensionally scaled variables when both the number and specific set of judges vary from one assessment to the next as discussed by the authors.
Abstract: Using a variant of the intraclass correlation coefficient (ICC), this program computes the reliability of dimensionally scaled variables when both the number and specific set of judges vary from one assessment to the next.
52 citations
TL;DR: Values of the intraclass correlation coefficient were positive and often of appreciable magnitude, indicating that measurements of attachment level and of change in attachment level within the same mouth are positively correlated.
Abstract: Using a data set from the Forsyth Dental Center consisting of repeated measurements of periodontal attachment level on 22 patients over 1 year, we performed correlation analyses at 4 time points (baseline, 1 month, 6 months and 9 months) for 3 units of measurement (sites, teeth and quadrants). Values of the intraclass correlation coefficient were obtained for the cross-sectional measurements and for changes from baseline. The values were positive and often of appreciable magnitude, indicating that measurements of attachment level and of change in attachment level within the same mouth are positively correlated. Taking sites rather than patients as the units of statistical analysis in comparative clinical trials in periodontology will therefore tend to produce underestimated standard errors and overstated statistical significance.
41 citations
TL;DR: This article explored various graphic characteristics associated with the visual analysis of single-subject data, and argued that quantitative adjuncts to visual analysis may facilitate the reliable interpretation of graphed data for a single subject.
Abstract: A study explored various graphic characteristics associated with the visual analysis of single-subject data. A sample of 20 rehabilitation therapists used visual analysis to rate 24 graphs of data sets using a traditional baseline/treatment (AB) format. Using the intraclass correlation approach, the authors assessed the interrater reliability and found that it ranged from .52 to .66 for each graph. Data analysis revealed that the graphic characteristics of level and mean shift were associated with consistent judgments across the raters, and that changes in slope across the two phases of a graph were associated with substantial rater disagreement. The authors discuss the implications of using visual and statistical procedures to analyze single-subject data, and argue that quantitative adjuncts to visual analysis may facilitate the reliable interpretation of graphed data for a single subject.
40 citations
TL;DR: The clinical gait analysis method was found to be a valid tool in comparison with 16-mm cinematography for the variables that were studied and the consistency of performance of the subjects during walking was examined.
Abstract: The purpose of this study was to compare a clinical gait analysis method using videography and temporal-distance measures with 16-mm cinematography in a gait analysis laboratory. Ten children with a diagnosis of cerebral palsy ( age = 8.8 ± 2.7 years) and 9 healthy children ( age = 8.9 ± 2.4 years) participated in the study. Stride length, walking velocity, and goniometric measurements of the hip, knee, and ankle were recorded using the two gait analysis methods. A multivariate analysis of variance was used to determine significant differences between the data collected using the two methods. Pearson product-moment correlation coefficients were determined to examine the relationship between the measurements recorded by the two methods. The consistency of performance of the subjects during walking was examined by intraclass correlation coeffi cients. No significant differences were found between the methods for the variables studied. Pearson product-moment correlation coefficients ranged from .79 to .95, and intraclass coefficients ranged from .89 to .97. The clinical gait analysis method was found to be a valid tool in comparison with 16-mm cine matography for the variables that were studied.
35 citations
TL;DR: In this paper, the Gini-Light-Margolin concept of partioning variance for qualitative data is used to establish correspondences between various kappa statistics and intraclass correlation coefficients under general conditions (multiple raters and polychotomous category systems).
Abstract: Using the Gini-Light-Margolin concept of partioning variance for qualitative data, correspondences are established between various kappa statistics and intraclass correlation coefficients under general conditions (multiple raters and polychotomous category systems). A measure of marginal symmetry for multiple ratings is also developed and is shown to have a proportion-of-variance explanation.
34 citations
TL;DR: In this inter‐rater agreement study of antenatal and neonatal variables collected in a large teaching obstetric unit, information routinely collected by hospital staff was compared with that collected by a specially trained physician and a social worker.
23 citations
TL;DR: The Zeiss Scheimpflug Cataract Video Camera was designed to photograph, store and analyze cataracts in a semi-automated fashion for cross-sectional and longitudinal studies and may be a useful instrument in monitoring lens changes in certain diseases and the effects of anti-cataract agents.
Abstract: The Zeiss Scheimpflug Cataract Video Camera was designed to photograph, store and analyze cataracts in a semi-automated fashion for cross-sectional and longitudinal studies. We conducted a reproducibility study of this system. Twenty-four normal and 61 cataractous eyes were photographed twice by each of two of the authors in the 90° meridian and microdensitometry was performed on each of the stored images. Reproducibility was then determined using the intraclass correlation coefficient to determine whether or not the differences encountered were due to variability in the system or due to actual differences among the images. The intraclass correlation in the lens nucleus was 0.995 with 95% confidence limits of. 992-.996. Therefore, reproducibility was 99.5%. In the anterior cortex, intraclass correlation was. 941 with 95% confidence limits of. 919-.959. In the posterior cortex intraclass correlation was. 905 with 95% confidence limits of. 870-.932. Reproducibility with this instrument was therefore excelle...
22 citations
TL;DR: Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight.
Abstract: Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight.
TL;DR: The interexaminer variability was nonsignificant in measurements of the three blood vessels under examination, and Umbilical artery measurements showed a better reliability and hold the greatest clinical applicability.
Abstract: A study was made of the interexaminer variability of Doppler velocity waveform determinations of the fetal circulation. Three investigators recorded Doppler ultrasound tracings of the blood velocity in the fetal thoracic and abdominal aorta and umbilical artery in 23 uncomplicated pregnancies. Of these recordings, a hard copy was made, and the pulsatility indices were computed. An analysis of variance was performed and the reliability calculated. The interexaminer variability was nonsignificant in measurements of the three blood vessels under examination. Both thoracic and abdominal aorta measurements showed poor reliability (intraclass correlation coefficient of reliability 0.30 and 0.19, respectively) due to high random errors. Umbilical artery measurements showed a better reliability (intraclass correlation coefficient of reliability 0.61), and, therefore, these hold the greatest clinical applicability.
TL;DR: The decomposition of observed scores into true scores and measurement error provides the classical conceptual framework for the analysis of reliability and Sensitivity coefficient is proposed as a more appropriate term for the classical reliability coefficient.
Abstract: The decomposition of observed scores into true scores and measurement error provides the classical conceptual framework for the analysis of reliability. The intraclass correlation coefficient (ICC) provides a general reliability coefficient that may be applied in many situations, providing that care is taken to formulate the appropriate ANOVA model. An illustrative analysis is described of a complex design involving two nested sources of error. An appropriate ICC is derived. The value of the information provided by such a reliability study, especially of the variance components, for designing a decision study is discussed. Because ICC is a function of both subject variability and measurement error, difficulties of interpretation can arise. The test theorist’s definition of reliability is argued to conflict with intuitive notions of this concept. Sensitivity coefficient is proposed as a more appropriate term for the classical reliability coefficient.
TL;DR: Results of the present study on repeatability complement the results of previous research into the criterion validity of questionnaire-derived information and suggest that information of relatively high quality may be obtained from such sources.
TL;DR: The study results suggest that the Motor Development Checklist, when administered by experienced raters, can provide consistent information regarding the spontaneous motor performance of persons with multiple disabilities.
Abstract: A study was conducted to determine the interrater and test-retest reliability of the Motor Development Checklist (Doudlah, 1976). Thirty-six subjects with diagnosed multiple disabilities and severe and profound mental retardation were evaluated by two experienced occupational therapists. Reliability was established by means of the intraclass correlation approach, and results indicated that coefficients ranged from .93 to .99. The study results suggest that the Motor Development Checklist, when administered by experienced raters, can provide consistent information regarding the spontaneous motor performance of persons with multiple disabilities. Implications for practice and future research are briefly discussed.
01 Oct 1988
14 Nov 1988
TL;DR: A statistical method is suggested for data classification using the interclass correlation coefficient (ICC) statistics as a criterion function.
Abstract: A statistical method is suggested for data classification using the interclass correlation coefficient (ICC) statistics as a criterion function. The theory of the statistics is represented and its characteristics has been investigated. An algorithm for data classification using ICC is also described. >