Multi-rater delta: extending the delta nominal measure of agreement between two raters to many raters

The need to measure the degree of agreement among R raters who independently classify n subjects within K nominal categories is frequent in many scientific areas. most popular measures are Cohen's kappa (R = 2), Fleiss' kappa, Conger's and Hubert's $\geq$ 2) coefficients, which have several defects. In 2004, delta coefficient was defined for case 2, did not defects coefficient. This article extends from 2 2. multi-rater has same advantages as with regard type coefficients: i) it intuitive easy interpret, because refers proportion replies that concordant non random; ii) summands give its value allow each category be measured accurately, no collapsed; iii) affected by marginal imbalance.