The data comes from Spotify’s Track Audio Features API. [1] [2] I believe this data was imported from the EchoNest project when Spotify acquired them [3] and i

The data comes from Spotify’s Track Audio Features API. [1] [2] I believe this data was imported from the EchoNest project when Spotify acquired them [3] and it’s possible that algorithms have improved since 2014 but not all old tracks have been re-analyzed. I would guess that this is what’s causing the discrepancies you’re seeing. [1] https://developer.spotify.com/console/get-audio-features-track/?id=11dFghVXANMlKmJXsNCbNl https://developer.spotify.com/console/get-audio-features-tra... [2] https://cln.sh/TfGPcj https://cln.sh/TfGPcj [3] https://en.wikipedia.org/wiki/The_Echo_Nest https://en.wikipedia.org/wiki/The_Echo_Nest