title: R coxph() warning: Loglik converged before variable
body: <p>I'm having some trouble using coxph().
  I've two categorical variables: Sex and Probable Cause, that I want to use as predictor variables. Sex is just the typical male/female but Probable Cause has 5 options.
  I don't know what is the problem with the warning message. Why does the cofidence intervals are from 0 to Inf and the p-values so high? </p>
  
  <p>Here's the code and the output:</p>
  
  <pre><code>&gt; my_coxph &lt;- coxph(Surv(tempo,status) ~ factor(Sexo)+ factor(Causa.provavel) ,           data=ceabn)
  Warning message:
  In fitter(X, Y, strats, offset, init, control, weights = weights,  :
  Loglik converged before variable  2,3,5,6 ; beta may be infinite. 
  
  &gt; summary(my_coxph)
  Call:
  coxph(formula = Surv(tempo, status) ~ factor(Sexo) + factor(Causa.provavel), 
  data = ceabn)
  
  n= 43, number of events= 31 
  
                                              coef exp(coef)  se(coef)     z Pr(&gt;|z|)
  factor(Sexo)macho                      7.254e-01 2.066e+00 4.873e-01 1.488    0.137
  factor(Causa.provavel)caca             2.186e+01 3.107e+09 9.698e+03 0.002    0.998
  factor(Causa.provavel)colisao linha MT 1.973e+01 3.703e+08 9.698e+03 0.002    0.998
  factor(Causa.provavel)indeterminado    9.407e-01 2.562e+00 1.683e+04 0.000    1.000
  factor(Causa.provavel)predacao         2.170e+01 2.655e+09 9.698e+03 0.002    0.998
  factor(Causa.provavel)predado          2.276e+01 7.659e+09 9.698e+03 0.002    0.998
  
                                         exp(coef) exp(-coef) lower .95 upper .95
  factor(Sexo)macho                      2.065e+00  4.841e-01    0.7947     5.368
  factor(Causa.provavel)caca             3.107e+09  3.219e-10    0.0000       Inf
  factor(Causa.provavel)colisao linha MT 3.703e+08  2.701e-09    0.0000       Inf
  factor(Causa.provavel)indeterminado    2.562e+00  3.904e-01    0.0000       Inf
  factor(Causa.provavel)predacao         2.655e+09  3.766e-10    0.0000       Inf
  factor(Causa.provavel)predado          7.659e+09  1.306e-10    0.0000       Inf
  
  Concordance= 0.752  (se = 0.059 )
  Rsquare= 0.608   (max possible= 0.987 )
  Likelihood ratio test= 40.23  on 6 df,   p=4.105e-07
  Wald test            = 7.46  on 6 df,   p=0.2807
  Score (logrank) test = 30.48  on 6 df,   p=3.183e-05
  </code></pre>
  
  <p>Thank you</p>