Don't post in html, the list scrambles your tables. Assuming your data looks
like this
> rater.id <- c(1, 2, 1, 3, 2, 3)
> observation <- c(1, 1, 2, 2, 3, 3)
> rating <- c(6, 7, 4, 6, 2, 4)
> dat <- data.frame(rbind(rater.id, observation, rating))
> dat
X1 X2 X3 X4 X5 X6
rater.id 1 2 1 3 2 3
observation 1 1 2 2 3 3
rating 6 7 4 6 2 4
We need to transpose the data and then use xtabs(). This will work as long as
there is not more than one rating on an observation by the same rater:
> t(dat)
rater.id observation rating
X1 1 1 6
X2 2 1 7
X3 1 2 4
X4 3 2 6
X5 2 3 2
X6 3 3 4
> tbl <- xtabs(rating~observation+rater.id, t(dat))
> tbl
rater.id
observation 1 2 3
1 6 7 0
2 4 0 6
3 0 2 4
If the 0's are a problem:
> tbl[tbl==0] <- NA
> print(tbl, na.print=NA)
rater.id
observation 1 2 3
1 6 7 <NA>
2 4 <NA> 6
3 <NA> 2 4
David L. Carlson
Department of Anthropology
Texas A&M University
-----Original Message-----
From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Chad Danyluck
Sent: Friday, October 9, 2015 4:02 PM
To: r-help@r-project.org
Subject: [R] Reformatting dataframe for use with icc()
Hello,
I want to determine the inter-rater reliability of ratings made from a
random selection of observers and observations. I plan to use the irr
package to calculate the ICC, however, my dataframe is not organized in a
way that the icc() function can handle. The icc() function works with
dataframes in the following format:
rater1 rater2 rater3...
observation
1 6 7 NA
2 4 NA 6
3 NA 2 4
...
My dataframe is organized in the following format:
rater.id 1 2 1 3 2 3 ...
observation 1 1 2 2 3 3 ...
rating 6 7 4 6 2 4 ...
I would like to reformat my dataframe as it is organized in the first
example but I am not sure how to go about doing this. Any suggestions would
be appreciated.
Kind regards,
Chad
--
Chad M. Danyluck, MA
PhD Candidate, Psychology
University of Toronto
“There is nothing either good or bad but thinking makes it so.” - William
Shakespeare
[[alternative HTML version deleted]]
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______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
