[R] Ordinal regression with some categories combined for some data

Thierry Onkelinx thierry.onkelinx at inbo.be
Sat Jan 16 20:11:24 CET 2016

Dear Bob,

I don't know any package that handles ordinal data the way you are looking
for. I'd just would comment on the ordinal regression. Would the time of
loss be the ordinal response? That seems inefficient to me when you have a
lot of time points (= lots of ordinal classes). IMHO the survival analysis
would make more sense.

Best regards,


ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
Kliniekstraat 25
1070 Anderlecht

To call in the statistician after the experiment is done may be no more
than asking him to perform a post-mortem examination: he may be able to say
what the experiment died of. ~ Sir Ronald Aylmer Fisher
The plural of anecdote is not data. ~ Roger Brinner
The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of data.
~ John Tukey

2016-01-15 16:48 GMT+01:00 Bob O'Hara <rni.boh op gmail.com>:

> Hi!
> I've been asked about a problem where I think I can see how to write
> the model, but don't know if it's been implemented in R. It's not
> something I work on a lot, so I'm hoping someone else can point me to
> an answer straight away.
> The researcher has been carrying out germination experiments: lost of
> seeds are put in several conditions (temperature humidity etc.), and
> every few days they are checked to see if they have germinated.
> Because the days are discrete I think it makes sense to view this as
> an ordinal regression problem (rather than as an interval censored
> survival analysis). But what makes this tricky is that there are days
> when the researcher only checked some seeds. So for some seeds the
> germination might fall into more than one category.
> Is there a package in R that can handle this, i.e. do an ordinal
> regression where for some observations the categories are interval
> censored? Or is it easier to go straight to a full interval-censored
> survival analysis?
> Bob
> --
> Bob O'Hara
> Biodiversity and Climate Research Centre
> Senckenberganlage 25
> D-60325 Frankfurt am Main,
> Germany
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