[R] Reformatting dataframe for use with icc()

[Chad Danyluck]

Indeed, I've worked with the solutions provided by others and the reshape
package has been very fluid to use. Thanks for the suggestion.

Chad

On Sat, Oct 10, 2015 at 4:56 PM, Frans Marcelissen <
fransiepansiekevertje at gmail.com> wrote:

> I think this is what reshape is made for...
> Frans
> --------------------------------------
>
> 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(rater.id,observation,rating)
>
> library(reshape)
> dat2<-melt(dat, id.vars = c('rater.id','observation'))
> cast(dat2,observation~rater.id)
> observation  1  2  3
>                1  6  7 NA
>                2  4 NA  6
>                3 NA  2  4
>
> 2015-10-10 20:15 GMT+02:00 David L Carlson <dcarlson at tamu.edu>:
>
>> 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-bounces at r-project.org] On Behalf Of Chad
>> Danyluck
>> Sent: Friday, October 9, 2015 4:02 PM
>> To: r-help at 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]]
>>
>> ______________________________________________
>> R-help at 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.
>> ______________________________________________
>> R-help at 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.
>>
>
>


-- 
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]]