title: Spotify: How is a track's popularity value determined?
body: <p>I've been working with the spotify meta data api, and I was trying to figure out exactly what the popularity field of a track meant (represented as a float, 1 being popular, 0 not).  I checked if there was a linear correlation between the float value and total plays as listed in spotify, but there definitely is not. I found three tracks by the same artist whose popularity values were all 0.61, one had 1.7 million plays, one had 1.6 million and another had ~140,000.  Unfortunately playcounts are not part of their meta data api.</p>
  
  <p>Does anybody know how they determine this value for each track? I'm guessing it might be a relative fraction of (plays/time on spotify) compared to the track with the most plays/time but I can't prove that. If you know I'd love to hear your thoughts. Thanks</p>