[R] lambda, uncertainty coefficient (& Somers D)
Frank E Harrell Jr
f.harrell at vanderbilt.edu
Tue Apr 18 16:11:42 CEST 2006
Antti Arppe wrote:
> Dear colleagues in R,
>
> Has anybody implemented the
>
> 1) (Goodman & Kruskal) lambda
>
> or the
>
> 2) (Thiel's) uncertainty coefficient
>
> statistics (in the asymmetric and symmetric forms), or is anyone aware
> that they might reside in some package? A search in the R archives
> does indicate that they are (somehow) part of the CoCo package, but I
> would rather not start learning how to transform my data into
> CoCo-format in order to access these functions, regardless of whether
> the CoCo versions are actually intended for calculating the actual
> statistic or for some other package internal purposes, as may
> sometimes be the case.
>
> Furthermore, it appears to me that the 'somers2' function in the Hmisc
> package applies Somers' D only to 2x2 and not larger tables. Am I
> mistaken, or does there exist somewhere else an implementation of the
> Somers' D statistic for the more general RxC tables? This was queried
> in 1999, but no response seemed then to be forthcoming.
Somers' D is for a 2-category response variable. X may have any number
of categories as long as they are ordered.
Frank Harrell
>
> Thanks and regards,
>
> -Antti Arppe
--
Frank E Harrell Jr Professor and Chair School of Medicine
Department of Biostatistics Vanderbilt University
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