Warning Message in R (Clogit Function with survival package)

[Hsu]

Dear All,

I used clogit function in R-studio with my research variable (BM2+BH3+WM2+WL3+FG2+FE3+RG2+RE3+Cost) .
This script is working though I got the following warning message. I would like to understand the meaning of that warning message.
What does it mean?

clogout1=clogit (RES~ASC+BM2+BH3+WM2+WL3+FG2+FE3+RG2+RE3+Cost+strata(STR),data=mydata)
Warning message:
In coxexact.fit(X, Y, istrat, offset, init, control, weights = weights, :
Ran out of iterations and did not converge

[DavoWW]

Hi Hsu,
Model convergence was not achieved given the maximum number of iterations specified (default=20). You can try increasing the iteration number as follows:

library(survival)
# help(coxph.control)
coxph.control()$iter.max

clogout1 <- clogit(RES~ASC+BM2+BH3+WM2+WL3+FG2+FE3+RG2+RE3+Cost+strata(STR),
                   data=mydata,
                   iter.max=30)

[Hsu]

@DavoWW

clogout1 <- clogit(RES~ASC+BM2+BH3+WM2+WL3+FG2+FE3+RG2+RE3+Cost+strata(STR),
                   data=mydata,
                   iter.max=30)

Dear @DavoWW
Thank you so much for your response.
But, I still receive the "warning message" like the following;

Warning message:
In coxexact.fit(X, Y, istrat, offset, init, control, weights = weights, :
Loglik converged before variable 1 ; beta may be infinite

[DavoWW]

I can't help much further - I suggest you seek local expert assistance.

[Hsu]

I can interpret it by reading some literature reviews.
Thank you so much for your suggestion.