inter-rater reliability

Question

Which inter-rater reliability methods are appropriate for ordinal or interval data?

Answer 1

From IRR on Wikipedia:

Either Pearson's r or Spearman's ρ can be used to measure pairwise correlation among raters using a scale that is ordered. Pearson assumes the rating scale is continuous; Spearman assumes only that it is ordinal. If more than two raters are observed, an average level of agreement for the group can be calculated as the mean of the r (or ρ) values from each possible pair of raters. Both the Pearson and Spearman coefficients consider only relative position. For example, (1, 2, 1, 3) is considered perfectly correlated with (2, 3, 2, 4).

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