[R] How to extract ICC value from irr package?

[Joshua Wiley]

Hi Chen,

>From the documentation (see ?icc)  "$value: the intraclass correlation
coefficient."

As an example:

> set.seed(1)
> result <- icc(matrix(rnorm(20), ncol = 2))
> result$value
[1] -0.3148786


HTH,

Josh

On Tue, Aug 3, 2010 at 8:50 AM, chen chao <chenchaor at gmail.com> wrote:
> Hi, all
>
>
> There are 62 samples in my data and I tested 3 times for each one, then I
> want to use ICC(intraclass correlation) from irr package to test the
> consistency among the tests.
> *combatexpdata_p[1:62] is the first text results and combatexpdata_p[63:124]
> * is the second one and *combatexpdata_p[125:186]* is the third.
>
> Here is the result:
>
> result<-icc(cbind(combatexpdata_p[1:62],combatexpdata_p[63:124],combatexpdata_p[125:186]),
> "twoway")
> result
> Single Score Intraclass Correlation
>
>  Model: twoway
>  Type : consistency
>
>  Subjects = 62
>    Raters = 3
>  ICC(C,1) = -0.0664
>
> F-Test, H0: r0 = 0 ; H1: r0 > 0
>  F(61,122) = 0.813 , p = 0.814
>
> 95%-Confidence Interval for ICC Population Values:
>  -0.184 < ICC < 0.086
>
>
> I can get the p value by result$p but when i try result$icc to get the ICC
> value, it doesn't work. Is there anybody here know how to extract the
> -0.0664 from the result?  Many thanks.
>
>
> --
> Chen, Chao
> Psychiatry
> University of Chicago
> 924 E 57th St, Chicago, IL 60637
> U. S. A.
> MOE Key Laboratory of Contemporary Anthropology and Center for
> Evolutionary Biology,
> School of Life Sciences and Institutes of Biomedical Sciences,
> Fudan University
> 220# Handan Road, Shanghai (200433)
> P.R.China
>
>        [[alternative HTML version deleted]]
>
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-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/