| Abstract: | By COHEN and others the kappa index was developed for measuring nominal scale agreement between two raters. This statistic measures the distance from the nullhypothesis of independent ratings of two observers. Here a modified kappa is introduced, which takes into account the distance between the marginal distributions, as well. This distance is interpreted as the so-called interobserver bias. Population analogues are defined for the modified kappa and a related conditional index. For these parameters asymptotic confidence intervals and tests are derived. The procedures are illustrated by fictitious and real examples. |
