[R] glm with family binomial and link identity

Martin Maechler m@ech|er @end|ng |rom @t@t@m@th@ethz@ch
Thu Apr 28 17:40:41 CEST 2022

>>>>> Ralf Goertz 
>>>>>     on Thu, 28 Apr 2022 17:13:08 +0200 writes:

    > Am Thu, 28 Apr 2022 16:48:14 +0200
    > schrieb Martin Maechler <maechler using stat.math.ethz.ch>:

    >> TLDR:  No, there was no such change in R 4.2.0

    > Yeah sorry, now there are three mails and what I really want to know is
    > in the third (from 28 Apr 2022 09:53:39 +0200):

    > On the other hand why do I get this following error at all?

    > Error in binomial(link = identity) : 
    > link "identity" not available for binomial family; available links are ‘logit’, ‘probit’, ‘cloglog’, ‘cauchit’, ‘log’

    > This is a bit misleading since identity is a legitimate link function
    > and works perfectly *when* *quoted*.

    > Short enough? :-)

Well, now you did not read what I wrote, cited here again :

> HOWEVER, this all has been documented for a long time,
> in  ?family == ?binomial

>   Note:

> 	 The ‘link’ and ‘variance’ arguments have rather awkward semantics
> 	 for back-compatibility.  The recommended way is to supply them as
> 	 quoted character strings, but they can also be supplied unquoted
> 	 (as names or expressions).  Additionally, they can be supplied as
> 	 a length-one character vector giving the name of one of the
> 	 options, or as a list (for ‘link’, of class ‘"link-glm"’).  The
> 	 restrictions apply only to links given as names: when given as a
> 	 character string all the links known to make.link are accepted.

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