title: Solr: boosting by date not returning in right order, is something wrong with my boost?
body: <p>I'm using Solr to search for events, and I need events to be boosted by date so that the closer and event is to the current date, the higher its score will be compared to an event with say the same name but a later date. So, "Alumni Reunion" in January 2015 should show up higher on the list of results than "Alumni Reunion" in October 2015.</p>
  
  <p>I read the Solr Relevancy FAQ, and this is the query I'm using in solr:</p>
  
  <pre><code>?q={!boost%20b=recip(abs(ms(NOW,dt_startdate)),3.16e-11,1,1)}searchterms&amp;sort=score desc
  </code></pre>
  
  <p>It definitely changes the order of the results, but the order is wrong. For example, one of my searches that gives me back four results is returning them as 2012, 2013, 2014, 2015 when it should be the opposite (April 2015 vs. April 2014, 2015 should show up first). I tried simply changing it to </p>
  
  <pre><code>sort=score asc
  </code></pre>
  
  <p>but rather than returning in the opposite order as I'd expect, the order was totally different; it went 2014, 2015, 2012, 2013</p>
  
  <p>What is wrong with my boost? I believe that without the boost, the relevancy should be the same for all of them, because the field that contains the terms I'm searching for is exactly the same for each. The order was actually <strong>better</strong> before I put the boost in; while it wasn't correct, it went 2014, 2015, 2013, 2012 which was closer than it is now. </p>
  
  <p>EDIT: I realize that the boost won't necessarily put it in date order, which is fine, but something from 9 months ago should certainly show up before something from 2012, especially since <strong>without</strong> the boost, the 2014 event was at the top of the list. Right now 2012 is showing up first. </p>
  
  <p><strong>EDIT 2 (important)</strong>: Ok, so I decided to check what the scores were on my four events, with and without the boost. </p>
  
  <p>2012: 0.37118697    boost: 0.005060354      </p>
  
  <p>2013: 0.4639837    boost: 0.005060354       </p>
  
  <p>2014: 0.55678046    boost: 0.0044278097 </p>
  
  <p>2015: 0.4639837     boost: 0.0044278097 </p>
  
  <p>So you can see that the boost is actually making the <em>newer</em> onces <em>worse</em> than the older ones. Why is it doing this? I don't really understand the equation that the boost is doing, so I don't know why it's making the scores worse.</p>