title: Starting value error in glm.nb in R
body: <p>I'm running a negative binomial GLM in R. Running the model with the pooled dataset works just fine, but I'm encountering several warning messages when I attempt to run the same model for some of the smaller un-pooled (separated by animal) datasets. The model contains 12 standardized continuous variables (6 variables, each in linear and quadratic form) . The offset term 'tot' is a numeric vector. Here's a sample of the model; the real one includes all 12 predictors:</p>
  
  <pre><code>nb.2 = glm.nb(Count ~ offset(log(tot)) + variable1, data=anim.2)
  </code></pre>
  
  <p>I have run this for several animals and am receiving some or all of the following warnings:</p>
  
  <pre><code>Error: no valid set of coefficients has been found: please supply starting values
  
  glm.fit: fitted rates numerically 0 occurred 
  
  glm.fit: algorithm did not converge
  </code></pre>
  
  <p>Numerous searches haven't yielded any clear answers on these warnings. Please advise if more information is needed to answer. Thanks!</p>