Hello,
The following code:
> binomial(identity)
Generates an error message:
Error in binomial(identity) :
link "identity" not available for binomial family; available links
are ?logit?, ?probit?, ?cloglog?, ?cauchit?, ?log?
While :> binomial("identity")
Yields an identity-binomial object that works as expected with stats::glm
The error in the first example mislead me during years. I thought
identity-binomial models were unsupported by R.
The documentation is correct but misleading too.
> The gaussian family accepts the links (as names) identity, log and inverse;
the binomial family the
> links logit, probit, cauchit, (corresponding to logistic, normal and Cauchy
CDFs respectively) log and
> cloglog (complementary log-log);
Without changing the language, this could be fixed by changing the error
messages to something more suggestive.
Suggestion:
Error in binomial(identity) :
name identity not available for binomial family; please use a character string
such as binomial("identity")
The documentation could be updated to insist on that.
The gaussian family accepts the links (as names) identity, log and inverse; the
binomial family the
links logit, probit, cauchit, (corresponding to logistic, normal and Cauchy CDFs
respectively) log and
cloglog (complementary log-log); [...] If the link function is given as a
character string, all families accept all link functions.
What do you think of that ?
--
Sincerely
Andr? GILLIBERT
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