title: Binary Classification
body: <p>Suppose instead of having labels already assigned to instances, I instead write a deterministic function from instances to labels that says,</p>
  
  <p>"If instance A satisfies some condition, label it 0. Else, label it 1."</p>
  
  <p>Then I run an ROC analysis on the resulting set of instances and labels.</p>
  
  <p>Can someone tell me what, exactly, I have done? Am I merely testing the discriminative ability of my function as a classifier?</p>
  
  <p>I'm a bit confused since in this case I am the one assigning labels. I am not assuming they are given and trying to learn a classifier, per se.</p>