Measuring Pairwise Agreement Among Many Observers. II. Some Improvements and Additions

Weighted kappa was defined as a measure of pairwise interobserver agreement for the case where the observers judging one subject are not necessarily the same as those judging another subject. In this paper improved formulas for the large sample variance of the weighted kappa statistic are derived, a new definition of interclass kappa coefficients is suggested, and the intraclass correlation coefficient is shown to be a special case of weighted kappa.