title: What's the correct way to handle Alias variable?
body: <p>I'm running a logistic regression &amp; got the error message </p>
  
  <pre><code>Error in vif.default(failure.survival.train) : 
  there are aliased coefficients in the model
  </code></pre>
  
  <p>My equation that was generating above message was </p>
  
  <pre><code>group.survival.train = glm(group ~ .,family = binomial(logit), data =   group.train)
  group_train_vif=vif(group.survival.train)
  </code></pre>
  
  <p>So, I try following things </p>
  
  <pre><code>alias( glm(group ~ .,family = binomial(logit), data = group.train) ) 
  </code></pre>
  
  <p>So I got following output </p>
  
  <pre><code>           (Intercept) group1 group2 group3 group4 group5 group6 group9
  group7         0           0    0       0      0     0      0      0         
  group8         0           0    0       0      0     0      0      0 
  </code></pre>
  
  <p>Does this mean that Group 7 &amp; 8 are linear dependent of Group 1-2-3-4-5-6-9 &amp; I need to remove both group 7 &amp; 8 from my model?</p>