[R] binomial(link="inverse")

Prof Brian Ripley ripley at stats.ox.ac.uk
Thu Sep 11 08:24:03 CEST 2008

On Wed, 10 Sep 2008, Thomas Lumley wrote:

> On Wed, 10 Sep 2008, Prof Brian Ripley wrote:
>> As to why the list of links known by name is as it is, that seems history. 
>> in part the White Book history of S.  I've always thought it an error that 
>> 'log' was a standard link for binomial, as the range does not match the 
>> specification of probabilities (and S did not do so, MASS Table 7.1 ).
> I think I added binomial("log"): log-binomial regression is quite popular and 
> useful in epidemiology (where effect sizes are small enough that keeping away 
> from the boundary may be less of a problem than people's inability to 
> understand odds ratios).

Yes.  My comment was about being "standard" and so easy to use 
unthinkingly.  Where a Poisson approximation to the binomial would be 
good, a log link is also going to be appropriate.  Had we then the 
infrastructure in place we have now, I would have been suggesting (like 
identity) that it be available via an (easy) user extension.

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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