[R] glm.fit: fitted probabilities numerically 0 or 1 occurred & glm.fit: algorithm did not converge

Michael Dewey lists at dewey.myzen.co.uk
Fri Aug 12 16:00:58 CEST 2016


Dear Shivi

Can you show us the output?

And please do not post in HTML as it will mangle your post into 
unreadability.

On 12/08/2016 10:10, Shivi Bhatia wrote:
> Hi Team,
>
> I am creating *my first* Logistic regression on R Studio. I am working on a
> C-SAT data where rating (score) 0-8 is a dis-sat whereas 9-10 are SAT. As
> these were in numeric form so i had as below created 2 classes:
>
> new$survey[new$score>=0 & new$score<=8]<- 0
> new$survey[new$score>=9]<- 1
> This works fine however the class still shows as "numeric" and levels shows
> as "NULL". Do i still need to use "as.factor" to let R know these are
> categorical variables.
>
> Also i have used the below code to run a logistic regression with all the
> possible predictor variables:
> glm.fit= glm(survey ~ support_cat + region+ support_lvl+ skill_group+
> application_area+ functional_area+
>           repS+ case_age+ case_status+ severity_level+
>           sla_status+ delivery_segmentation, data = SFDC, family = binomial)
>
> But it throws an error:-
> Warning messages:
> 1: glm.fit: algorithm did not converge
> 2: glm.fit: fitted probabilities numerically 0 or 1 occurred
>
> I checked online for the error and it says:
> "glm() uses an iterative re-weighted least squares algorithm. The algorithm
> hit the maximum number of allowed iterations before signalling convergence.
> The default,
> documented in ?glm.control is 25."
>
> Kindly suggest on the above case and if i have to change my outcome var as
> as.factor.
>
> Thank you, Shivi
>
> 	[[alternative HTML version deleted]]
>
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-- 
Michael
http://www.dewey.myzen.co.uk/home.html



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