Hi, Sorry, it's ok I've figured it out using the as.matrix function! Cheers,
Julia. ________________________________________ From: Scot W. McNary [smcn...@charm.net] Sent: 23 December 2009 15:41 To: Julia Myatt Cc: r-help@r-project.org Subject: Re: [R] Cohen's kappa, unequal score ranges Julia, I was able to get your toy data to work, using the n * 2 data frame, which is what ckappa takes as input. > chk <- data.frame(matrix(c( + 3, 4, + 4, 3, + 2, 1, + 2, 1, + 5, 1, + 2, 4), byrow = TRUE, ncol = 2)) > chk X1 X2 1 3 4 2 4 3 3 2 1 4 2 1 5 5 1 6 2 4 > sk <- ckappa(chk) > sk $table 1 2 3 4 5 1 0 0 0 0 0 2 2 0 0 1 0 3 0 0 0 1 0 4 0 0 1 0 0 5 1 0 0 0 0 $kappa [1] -0.0909091 > str(sk) List of 2 $ table: num [1:5, 1:5] 0 2 0 0 1 0 0 0 0 0 ... ..- attr(*, "dimnames")=List of 2 .. ..$ : chr [1:5] "1" "2" "3" "4" ... .. ..$ : chr [1:5] "1" "2" "3" "4" ... $ kappa: num -0.091 Hope this helps, Scot Julia Myatt wrote: > Hi Jim, > > Thanks for your help, I tried that function which did result in an output. > The only issue now is my summary looks like this: > > Length Class Mode > table 16 -none- numeric > kappa 1 -none- numeric > > Not what I was expecting, this was the case when my data was in the following > format: > > ob1 ob2 > 1 3 4 > 2 4 3 > 3 2 1 > 4 2 1 > 5 5 1 > 6 2 4 > > I then tried entering my data as a matrix like the one below (all this data > is made up until I get it to work!): > > p1 p2 p3 p4 p5 > p1 3 1 0 4 2 > p2 3 5 0 7 1 > p3 2 3 4 6 3 > p4 4 1 0 4 0 > p5 8 2 0 2 5 > > and this resulted in the same type of output: > > Length Class Mode > table 36 -none- numeric > kappa 1 -none- numeric > > If that is the kappa output (1) something isn't right as I purposely made the > data without good interrater reliability! I was wondering if you have anymore > tips as to what I am doing wrong? I'm afraid I'm very new to R so don't even > know the basics!! > > Thanks for all your help, > > Julia. > > > ________________________________________ > From: Jim Lemon [...@bitwrit.com.au] > Sent: 23 December 2009 02:15 > To: Julia Myatt > Cc: r-help@r-project.org > Subject: Re: [R] Cohen's kappa, unequal score ranges > > On 12/23/2009 01:58 AM, Julia Myatt wrote: > >> Hi, >> >> I am having problems getting cohen's kappa to work. I have been using the >> function: >> >> >> >>> <-ckappa(x,y) >>> >>> >> from the psy package. >> >> I am trying to test for inter-observer reliability, I have 2 observers and >> 26 categories, however, the two observers might not necessarily have the >> same range of categories (I have unequal score ranges). However, I thought R >> could cope with this. >> >> Each time I try the function above I get the following output: >> >> >> >>> Error in ckappa(ob1, ob2) : unused argument(s) (ob2) >>> >>> >> I got this even when I altered the data to have equal score ranges, >> therefore I am not sure what this means or what I should do!! >> >> Any help in this area would be much appreciated, or anything about the best >> way to deal with inter-observer reliability (my data is all categorical), >> >> >> > Hi Julia, > The ckappa function only takes one argument, a rater by object matrix or > dataframe of scores. Try: > > ckappa(cbind(ob1,ob2)) > > Jim > > ______________________________________________ > R-help@r-project.org mailing list > 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. > -- Scot McNary smcnary at charm dot net ______________________________________________ R-help@r-project.org mailing list 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.
