Note that the sample size consists of the number of observations with which evaluators are compared. Cohen specifically discussed in his papers two evaluators. The kappa is based on the chi-square array, and the pr(s) is obtained by the following formula: As the overall probability of the concordance is Σi πii, the probability of the concordance under the zero hypothesis is equal to Σi πi + π + i. Also note that Σi πii = 0 does not mean a match and that Σi πii = 1 indicates a perfect match. Kappa`s statistics are defined in such a way that greater value implies greater consistency: as Marusteri and Bacarea have found (9), there is never 100% certainty about the research results, even if statistical significance is achieved. The statistical results for testing hypotheses about the relationship between independent and dependent variables become insignificant in the event of inconsistency in the evaluation of variables by the evaluators. If compliance is less than 80%, more than 20% of the analyzed data is defective. With a reliability of only 0.50 to 0.60, it must be understood that 40% to 50% of the analyzed data is defective. If kappa levels are less than 0.60, the confidence intervals above the kappa received are so large that it can be assumed that about half of the data could be false (10). It is clear that statistical significance means little when there are so many errors in the results tested. No.

.B. You cannot reliably compare Kappa values from different studies, as Kappa is sensitive to the prevalence of different categories. That is, if one category is observed more frequently in one study than another, Kappa may indicate a difference in compliance between evaluators that is not attributable to the evaluators. Cohen kappa statistics κ are a measure of the concordance between the categorical variables X and Y. For example, kappa can be used to compare the ability of different evaluators to classify subjects into one group among others. Kappa can also be used to assess the concordance between alternative categorical assessment methods when new techniques are studied. Cohen`s Kappa measures the concordance between two evaluators who divide each of the N elements into mutually excluded C categories. The definition of κ {textstyle kappa } is as follows: Note that the Gwet conformity coefficient does not depend on the assumption of independence between evaluators, so you can use it to reflect the magnitude of the concordance in more contexts than kappa. (kappa=dfrac {sum pi_ {ii}- sum pi_ {i+} pi_ {+i}} }{1-sumpi_ {i+} pi_ {+i}) Altman cites the results of Brostoff et al. in a comparison not of two human observers, but of two different evaluation methods. These methods are rast (radioallergosorbent test) and MAST (multi-RAST) for the examination of individuals` sera for the search for specifically reactive IgE in the diagnosis of allergies. Five categories of results were recorded by each method: po being the observed relative correspondence between the evaluators (identical to accuracy) and pe is the hypothetical probability of random convergence, with the observed data being used to calculate the probabilities of each observer who sees each category by chance.

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