Agreement Measures Statistics

For ordination data, where there are more than two categories, it is useful to know whether the evaluations of the various counsellors end slightly or vary by a significant amount. For example, microbiologists can assess bacterial growth on cultured plaques such as: none, occasional, moderate or confluence. In this case, the assessment of a plate given by two critics as “occasional” or “moderate” would mean a lower degree of disparity than the absence of “growth” or “confluence.” Kappa`s weighted statistic takes this difference into account. It therefore gives a higher value if the evaluators` responses correspond more closely with the maximum scores for perfect match; Conversely, a larger difference in two credit ratings offers a value lower than the weighted kappa. The techniques of assigning weighting to the difference between categories (linear, square) may vary. Term ii is the probability that both have placed the film in the same category i, and the overall probability of an agreement is the overall probability of the agreement. Ideally, all observations or most observations are ranked on the main diagonal, which means perfect harmony. Cohens Kappa () calculates the agreement between observers taking into account the agreement expected by chance as follows: In a table 3 x 3, you will find here two options that would not allow an agreement at all (what a census indicates): one is often interested in whether the measurements of two (sometimes more than two) different observers or by two different techniques result in similar results. This is called concordance or condore or reproducibility between measurements. Such an analysis examines the pairs of measurements, either categorically or numerically both, with each pair being performed on a person (or a pathology slide or an X-ray). Cohens coefficient Kappa () is a statistic used to measure reliability between advisors (and also the reliability of inter-raters) for qualitative (categorical) elements.

[1] It is generally accepted that this is a more robust indicator than a simple percentage of the agreement calculation, since the possibility of a random agreement is taken into account. There are controversies around Cohens Kappa because of the difficulty of interpreting the indications of the agreement. amazon greens powder