Showing papers on "Intraclass correlation published in 1985"

Reliability of Observational Kinematic Gait Analysis

Abstract: Gait analysis, like all clinical assessments, is subject to measurement error. Specification of the extent of measurement error is imperative before drawing conclusions from any test. The purpose of this study was to determine the within-rater and between-rater reliability of observational gait analysis in a pediatric sample wearing knee-ankle-foot orthoses. Three expert observers, using a 3-point scale, rated videotaped gait kinematics of 15 children who had lower limb disability and who wore braces. The rating sessions were then repeated, with one month between sessions. Total agreement (identical ratings), both between-raters and within-raters, occurred in two-thirds of the observations, and an additional 29% of the observations differed by one point. Between-rater intraclass correlation coefficient type 2,1 was .73; within-rater Pearson product-moment correlation averaged .60. Observational kinematic gait analysis appears to be a convenient, but only moderately reliable, technique.

Grading of tenderness as a source of interrater error in the Ritchie articular index.

Abstract: To assess the effect of grading of tenderness on the interrater reliability of the Ritchie articular index (RAI), 3 physicians recorded independent joint scores on each of 18 patients, examined in random order Our results indicate that close agreement (Intraclass Correlation Coefficient = 085) can be achieved on global RAI scores, and that raters can achieve reasonable agreement (kappa = 040-059) on the absolute presence or absence of tenderness of individual joints By contrast, interrater agreement hardly exceeds the chance level (kappa = 0008-0148) when degree of tenderness is independently assessed The grading system of the RAI may thus be implicated as an important source of the instrument's interrater error

Intraclass correlations of periodontal measurements.

Abstract: Components of variance and intraclass correlation coefficients were computed for changes in attachment level, pocket depth, gingival and plaque index scores for 5 groups of treated periodontal disease patients and 1 group of untreated subjects with periodontal disease. The intraclass correlation coefficients for attachment level change ranged from 0.011 to 0.165 (median 0.067), while intraclass correlation coefficients for pocket depth changes ranged from -0.009 to 0.178 (median 0.071). These intraclass correlation coefficients were much lower than those computed for changes in measurements of plaque which ranged from 0.086 to 0.568 (median 0.268) or gingival inflammation which ranged from 0.119 to 0.522 (median 0.264). Intraclass correlation coefficients at baseline for pocket depths ranged from 0.000 to 0.199 (median 0.053), for plaque accumulation from 0.121 to 0.531 (median 0.222) and for gingival inflammation from 0.229 to 0.596 (median 0.391). The differences in the intraclass correlation coefficients between pocket depth and attachment level on the one hand and plaque accumulation or gingival inflammation on the other could not be explained on the basis of differences in the measurement scale employed, since collapsing measurement scales had little effect on the intraclass correlation coefficients. The observed larger intraclass correlation coefficients for changes in plaque and gingival indices suggest a larger role for host contribution to these measurements. In contrast, the data suggest that the major but by no means the sole factor determining the variability of attachment level or pocket depth changes is the nature of the local factors.

Normalizing and variance stabilizing transformations for intraclass correlations

Abstract: A concept of normalizing transformations of statistics is constructed on the basis of the rate of convergence to normality. The concept is applied to derive a normalizing transformation of a maximum likelihood estimate of intraclass correlation coefficient in ap-variate normal sample. Numerical comparisons are made to examine whether the proposed transformation is efficient to achieve normality. The relationship between normalization and variance stabilization is also considered.

The analysis of intraclass correlation in multiple samples.

Abstract: Summary A unified methodology is presented for the analysis of intraclass correlation in two or more samples, with emphasis on application to family studies. The methodology provides point and interval estimates of a common intraclass correlation in data having either fixed or variable class sizes. Tests of homogeneity for intraclass correlation coefficients are also discussed.

A note on statistical methods adjusting for intraclass correlation

Abstract: On utilise un resultat sur les distributions de Robbins et Pitman (1949) pour obtenir une procedure de calcul exacte des vraies p-valeurs des tests de signification