How is weighted kappa calculated?
The weighted value of kappa is calculated by first summing the products of all the elements in the observation table by the corresponding weights and dividing by the sum of the products of all the elements in the expectation table by the corresponding weights.
How do you know if Inter rater is reliable?
Inter-Rater Reliability Methods
- Count the number of ratings in agreement. In the above table, that’s 3.
- Count the total number of ratings. For this example, that’s 5.
- Divide the total by the number in agreement to get a fraction: 3/5.
- Convert to a percentage: 3/5 = 60%.
When to use weighted kappa for inter rater reliability?
I know from the literature that intra- and inter-rater reliability are commonly calculated for these scales using weighted kappa.
Why are weighted Kappas and SPSS not the same?
A weighted version would precisely take into account the baseline occurrence of ratings when appraising relative-differences. The computations of the weighted kappas are correct as given in the SPSS add-in. The reason that they don’t agree for your two cases (A, E; A, M) is that the two sets have different marginal distributions.
What does a weighted kappa mean on a Likert scale?
Samy Azer, to clarify my reasoning on a weighted kappa: we are using ordinal Likert scales, where a 1 rating means very low or none and 2-5 indicate increasing degrees of the variables (but they are not necessarily evenly spaced).
Is there a weighted kappa for cerebral atrophy?
I am working with ordinal scales for cerebral atrophy (ratings 0 to 4) and vascular burden (ratings 0 to 3) assessed by two raters. I have installed the extension bundle for weighted kappa from SPSS (version 25) but I keep getting the error message “some ratings are less than one this command is not executed”.