title: R Survival Analysis: error in survreg using Weibull
body: <p>I'm trying to replicate some survival analysis using the Weibull distribution that I have previously produced in SAS - I'm now working from an unlicensed machine so am using R (both from Windows). My (right censored) input data looks like:</p>
  
  <pre><code>&gt; head(mydata)
    ID         Key  Time  Score    Event    Censor
  1 1231231    ZXC   28   182.34   0      1
  2 4564564    ASD   28   320.04   0      1
  3 7897897    QWE   28   306.32   0      1
  4 9879879    QWE   28   211.92   0      1
  5 6546546    ASD   28   276.14   0      1
  6 3213213    ZXC   28   331.50   0      1
  </code></pre>
  
  <p>with Event and Censor being binaries, Score varying between about 150 and 450 and Time between 1 and 28. There are some 30,000 rows in the input dataset.</p>
  
  <p>When I try:</p>
  
  <pre><code>mydatasr &lt;- survreg(Surv(Time, Censor) ~ Score, dist = "w")
  </code></pre>
  
  <p>I get a warning message:</p>
  
  <blockquote>
    <p>In survreg.fit(X, Y, weights, offset, init = init, controlvals = control,  : Ran out of iterations and did not converge, </p>
  </blockquote>
  
  <p>And no output.</p>
  
  <p>I've searched for this msg online (and through this site) but have not managed to find anything that indicates what the problem might be.  I had no convergence issues putting the same data through (proc logistic and) lifereg in SAS.</p>