# kripp.alpha: calculate Krippendorff's alpha reliability coefficient In irr: Various Coefficients of Interrater Reliability and Agreement

## Description

calculates the alpha coefficient of reliability proposed by Krippendorff

## Usage

 `1` ``` kripp.alpha(x, method=c("nominal","ordinal","interval","ratio")) ```

## Arguments

 `x` classifier x object matrix of classifications or scores `method` data level of x

## Value

A list with class '"irrlist"' containing the following components:

 `\$method` a character string describing the method. `\$subjects` the number of data objects. `\$raters` the number of raters. `\$irr.name` a character string specifying the name of the coefficient. `\$value` value of alpha. `\$stat.name` here "nil" as there is no test statistic. `\$statistic` the value of the test statistic (NULL). `\$p.value` the probability of the test statistic (NULL). `cm` the concordance/discordance matrix used in the calculation of alpha `data.values` a character vector of the unique data values `levx` the unique values of the ratings `nmatchval` the count of matches, used in calculation `data.level` the data level of the ratings ("nominal","ordinal", "interval","ratio")

## Note

Krippendorff's alpha coefficient is particularly useful where the level of measurement of classification data is higher than nominal or ordinal.

Jim Lemon

## References

Krippendorff, K. (1980). Content analysis: An introduction to its methodology. Beverly Hills, CA: Sage.

## Examples

 ```1 2 3 4 5 6 7 8 9``` ``` # the "C" data from Krippendorff nmm<-matrix(c(1,1,NA,1,2,2,3,2,3,3,3,3,3,3,3,3,2,2,2,2,1,2,3,4,4,4,4,4, 1,1,2,1,2,2,2,2,NA,5,5,5,NA,NA,1,1,NA,NA,3,NA),nrow=4) # first assume the default nominal classification kripp.alpha(nmm) # now use the same data with the other three methods kripp.alpha(nmm,"ordinal") kripp.alpha(nmm,"interval") kripp.alpha(nmm,"ratio") ```

### Example output

```Loading required package: lpSolve
Krippendorff's alpha

Subjects = 12
Raters = 4
alpha = 0.743
Krippendorff's alpha

Subjects = 12
Raters = 4
alpha = 0.815
Krippendorff's alpha

Subjects = 12
Raters = 4
alpha = 0.849
Krippendorff's alpha

Subjects = 12
Raters = 4
alpha = 0.797
```

irr documentation built on May 30, 2017, 3:13 a.m.