title: Computing similarity between two lists
body: <p>EDIT:
  as everyone is getting confused, I want to simplify my question. I have two ordered lists. Now, I just want to compute how similar one list is to the other.</p>
  
  <p>Eg,</p>
  
  <pre><code>1,7,4,5,8,9
  1,7,5,4,9,6
  </code></pre>
  
  <p>What is a good measure of similarity between these two lists so that order is important. For example, we should penalize similarity as 4,5 is swapped in the two lists?</p>
  
  <p>I have 2 systems. One state of the art system and one system that I implemented. Given a query, both systems return a ranked list of documents. Now, I want to compare the similarity between my system and the "state of the art system" in order to measure the correctness of my system. Please note that the order of documents is important as we are talking about a ranked system. 
  Does anyone know of any measures that can help me find the similarity between these two lists.</p>