Kappa will only address its maximum theoretical value of 1 if the two observers distribute codes in the same way, i.e. if the corresponding totals are the same. Everything else is less than a perfect match. Nevertheless, the maximum value Kappa could achieve helps, as uneven distributions help interpret the actual value received from Kappa. The equation for the maximum is:[16] Note that Cohens Kappa only measures the agreement between two advisers. For a similar level of match (Fleiss` kappa) used if there are more than two spleens, see Fleiss (1971). The Fleiss kappa is, however, a multi-rated generalization of Scott Pi`s statistic, not Cohen`s kappa. Kappa is also used to compare performance in machine learning, but the steering version, known as Informedness or Youdens J-Statistik, is described as the best for supervised learning. [20] We find that in the second case, it shows a greater resemblance between A and B than in the first.
Indeed, if the percentage of agreement is the same, the percentage of agreement that would occur „by chance” is much higher in the first case (0.54 vs. 0.46). Some researchers have expressed concern about the tendency to take into account the frequency of observed categories as circumstances, which may make it unreliable for measuring matches in situations such as the diagnosis of rare diseases. In these situations, the S tends to underestimate the agreement on the rare category. [17] This is why the degree of convergence is considered too conservative. [18] Others[19][citation necessary] dispute the assertion that kappa „takes into consideration” the coincidence agreement. To do this effectively, an explicit model of the impact of chance on councillors` decisions would be needed. The so-called random adjustment of Kappa`s statistics assumes that, if they are not entirely sure, the advisors simply guess – a very unrealistic scenario. The overall probability of an incomparable agreement is the probability that they have agreed on a yes or no, i.e. Kappa is an index that takes into account the agreement observed in relation to a basic agreement. However, investigators must carefully consider whether Kappa`s core agreement is relevant to the research issue.
