Showing papers on "Intraclass correlation published in 1979"
TL;DR: In this article, the authors present guidelines for choosing among six different forms of the intraclass correlation for reliability studies in which n target are rated by k judges, and the confidence intervals for each of the forms are reviewed.
Abstract: Reliability coefficients often take the form of intraclass correlation coefficients. In this article, guidelines are given for choosing among six different forms of the intraclass correlation for reliability studies in which n target are rated by k judges. Relevant to the choice of the coefficient are the appropriate statistical model for the reliability and the application to be made of the reliability results. Confidence intervals for each of the forms are reviewed.
21,185 citations
TL;DR: The proper analysis of data from a reliability study is shown to depend on the planned design and analysis of the clinical or field trial to be conducted following the reliability trial.
Abstract: A statistical model is given for representing the several components of variability present in measurements (e.g., DMFS scores) given by examiners to patients. Methods for making inferences about the intraclass correlation coefficient of reliability are presented and illustrated on a real set of data. The proper analysis of data from a reliability study is shown to depend on the planned design and analysis of the clinical or field trial to be conducted following the reliability trial.
85 citations
TL;DR: In this article, a nonparametric measure of intraclass correlation based on the probability of certain types of concordances among the observations and which can be estimated from ranked data is proposed.
Abstract: A nonparametric measure of intraclass correlation based on the probability of certain types of concordances among the observations and which can be estimated from ranked data is proposed. One estimator whose variance can be estimated in an unbiased way is shown to be asymptotically normally distributed. Properties of the measure and its estimator are studied for a normal model; in particular the method is shown to provide a relatively powerful test of the null hypothesis of zero intraclass correlation in a normal population. The intraclass correlation coefficient is often used as a measure of the degree to which individuals from the same family resemble one another in some variable such as height or weight. From a random sample of families and a random selection of individuals from each family, both the between and within family components of variance can be estimated and an estimate of the intraclass correlation obtained. When the observations are ranks this approach is not feasible since direct estimates of the components of variance are not available. An example occurs in a study of aggressiveness in male red grouse (Moss, Watson & Parr, 1974). One measure of aggressiveness of an individual bird is a dominance rank, the position of that bird in the dominance hierarchy of a given group of birds. Comparison of the degree of familial resemblance in different populations is complicated by the fact that the data are ranks and that dominance hierarchies can be variable in size with different family sizes. The development of standard test statistics, such as the Kruskal-Wallis statistic (Kruskal, 1952), as measures of intraclass correlation is unsatisfactory because of the complicated dependence on the structure of the sample; see ? 6. In this paper a measure of intraclass correlation is proposed which overcomes this problem. It is independent of the structure of the sample and it can be estimated in an unbiased way from ranked data. The interclass rank correlation coefficients, Kendall's Xr and Spearman's p (Kendall, 1955), can be interpreted in terms of probabilities of concordances among the observations from a bivariate distribution. In response to Hill (1974), Kerridge (1975) has used this probabilistic interpretation of r in an analysis of Football League results. The measure presented in the present paper is based on concordances among observations from a population in which individuals occur in families. Its properties for a general class of populations are discussed and some particular results for a one-way classification model with normally distributed effects are presented. The power of the associated test is assessed for a normal model for a range of sample structures.
47 citations
33 citations
TL;DR: In this article, Bartko's and Winer's intraclass correlation reliability methods are assessed for sets of ratings and dichotomous test score data and internal consistency estimates of reliability are demonstrated.
Abstract: Bartko's and Winer's intraclass correlation reliability methods are assessed. Alternative intraclass correlation techniques and internal consistency estimates of reliability are demonstrated for sets of ratings and dichotomous test score data.
2 citations