[R] not R question : alternative to logistic regression

S Ellison S.Ellison at lgc.co.uk
Fri Nov 16 00:04:41 CET 2007

Probabilities can only be even approximately linearly related to a
continuous predictor variable for a limited range, otherwise the model
will predict probabilities below 0 or above 1.

At some point, they have to tail off... unless you are modelling
something trivial like 'probability of being above the x'th quantile...'

But there's no particular reason your logistic regression has to be
based on a linear predictor scale. Take logs or otherwise transform the
predictor if that is justified by the underlying process or the data? 

Steve E

>>> <markleeds at verizon.net> 11/15/07 8:03 PM >>>
I was just curious if anyone knew of an alternative model to logistic
regression where the probabilities seems pretty linear to the predictor
rather than having that S shape that probit and logit assume.

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