[R-sig-phylo] fitContinuous in geiger: positive log-likelihoods when trait values <1

Nick Matzke matzke at berkeley.edu
Mon Mar 7 21:37:48 CET 2011


Hi all,

It seems to be a popular week for questions!

I am running fitContinuous on a variety of continuous trait 
data.  I am noticing that when the traits are in units where 
the max is less than 1 (these are not ratio data, though), 
many of the various models produce log-likelihoods that are 
positive, which ought to be impossible.

If I rescale the trait values, e.g. by multiplying them by 
100, the problem goes away and all log-likelihoods are 
negative, and come out somewhat similar to each other 
between the BM, OU, etc. models, as one would expect.

Any hint about why this might be?

Cheers,
Nick


-- 
====================================================
Nicholas J. Matzke
Ph.D. Candidate, Graduate Student Researcher

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