You could run the cor function on a small dataset where you know the
values of tau-a and/or tau-b (either because you hand computed them,
or found an example on the internet showing the difference), that
would give some good evidence as to which is used.
Or you could look at the source code, R is open source afterall.
On the jittering question: are you comfortable with a method that
would give a different answer every time you run it?
On Thu, Mar 6, 2014 at 9:41 PM, David Parkhurst <parkhurs at imap.iu.edu>
wrote:> How can I find out whether the cor function with method="Kendall"
computes
> Kendall's tau-a or tau-b. I understand that tau-b deals better with
ties,
> and I'm wanting to look for correlation in two variables that have lots
of
> ties (especially lots of zeroes for one of them). The information provided
> by ?cor does not specify which is computed.
> And a question: am I better off to jitter the variables before computing
> tau, given the many ties?
>
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--
Gregory (Greg) L. Snow Ph.D.
538280 at gmail.com