1

我正在尝试用 R 中的置信区间计算加权 kappa。

我无法理解为什么 DescTools::CohenKappa 和 irr::kappa2 这两个函数会给出不同的输出。我需要使用前者（DescTools::CohenKappa），因为我需要置信区间，但想知道为什么这些会产生不同的结果？

DescTools::CohenKappa:

      kappa      lwr.ci      upr.ci 
-0.24584718 -0.45930367 -0.03239068

irr::kappa2:

 Cohen's Kappa for 2 Raters (Weights: 0,0.25,1)

 Subjects = 20 
   Raters = 2 
    Kappa = 0.378 

        z = 1.71 
  p-value = 0.0878

这是一个例子：

library(irr)
library(DescTools)

## Data

test = structure(list(fi.cat = structure(c(2L, 2L, 2L, 2L, 2L, 1L, 1L, 
                                           2L, 3L, 2L, 1L, 2L, 1L, 1L, 
                                           3L, 3L, 2L, 2L, 1L, 1L), .Label = c("non-frail","prefrail", "frail"), class = "factor"), 
                      fp.cat = structure(c(2L,2L, 2L, 2L, 3L, 1L, 2L, 
                                           1L, 3L, 2L, 1L, 2L, 1L, 1L, 
                                           2L, 3L, 2L, 3L, 1L, 1L), .Label = c("non-frail", "prefrail", "frail"), class = "factor")), 
                 row.names = c(NA,20L), class = "data.frame")

## DescTools::CohenKappa

m = table(test$fi.cat, test$fp.cat) # create confusion matrix (i.e. cross tabulation)

wm = matrix(c(
  0, 0.25, 1,
  0.25, 0, 0.25,
  1, 0.25, 0), ncol=3, byrow=TRUE # my weights
)

kappa1 = DescTools::CohenKappa(m, weights=wm, conf.level=0.95) 

## irr::kapp2

kappa2 = irr::kappa2(test[, c("fi.cat", "fp.cat")], c(0, 0.25, 1))
4

0 回答 0