Volume 4’s illusion of unpopularity

In a recent Reddit post, I showed a scatterplot showing each Black Sabbath studio album’s playcount from LastFM. Volume 4 was the absolute lowest — even beneath every Ian Gillan and Tony Martin album (no disrespect to either, I’m just talking data and conventional perception). I and most commenters were surprised so here are some more screenshots explaining how that happened.

Table showing the same data from June 19. The only albums lower than Vol. 4 are obscure bootlegs.

Looking at my column chart for their Spotify popularity scores (as of today), I noticed one release of Vol 4 has a popularity score of 2 while the others are more respectable and what we’d expect.

Spotify contains several releases of each album. Some countries get even more than USA users.

When I get my data from MusicBrainz‘s API, it looks like this:

Children of the Grave is a bootleg of Vol 4 so it is the same “release group” from MusicBrainz.

MusicBrainz is where I get info about artists and all their albums and tracks. I’ve collapsed the data for each album so you can see there are 12 total versions of Vol 4. I push that list to LastFM to pull the number of listeners and playcounts for each album and track.

A “release group” is an album. A “release” is each edition or version of that album — Remastered, collectors’s edition, comes with a poster, whatever.

LastFM doesn’t have data for all releases but sends what it does have. For reasons I won’t bore you with, I only grab data for the first release in each release group which, in this case, is that f***ing Children of the Grave bootleg. As I write this, I have a solution in mind that should also fix another oddity in my app.

I hope you’re nerdy enough to have enjoyed this.