A recent blog post by Dualnoise on optimal playlists go me thinking about playlists. My mp3 player is filled with running songs that are “shuffled.”
I put shuffled in quotes because I’m not sure how the shuffling algorithm works and if it is really a good pseudo-random ordering of the songs. But at the end of the day, I don’t want the songs to be random. I want them to be random-ish.
My mp3 player has a couple of shuffle varieties. One shuffle variety appears to play songs that were recently uploaded more frequently than old songs. I like this, but I change the songs so rarely that it isn’t very useful any more.
Another mode shuffles through all the songs, not repeating a song until all are played in a session (a run starts a new session starts). I never run long enough to repeat any of the songs. Therefore, I hear each song no more than once per run. But the memory resets every time I turn off the mp3 player, so I hear some songs during every run and rarely hear other songs. I just updated my playlist and found a handful of songs that I have not heard this year.
I’m sure everyone has that song that always plays every time you turn on your mp3 player. For me, that song is Bruce Springsteen’s “Born in the USA” (at least it was until I removed it).
I know this is what “random” looks like, but I don’t like it: I don’t want to hear some songs too much and others not enough. I conclude that my “optimal” randomly ordered playlist is a very fake looking random sequence of songs to ensure that all songs are not over- or under-played. I feel like a fraud just admitting that!
This article suggests that playlists advertised as random may in fact be less random than we are led to believe. It discusses playlists that an mp3 player may create (kinda like Pandora) rather than a preset playlist. They tested iTunes’s Smart playlists and found that iTunes preferred Lionel Richie songs. Interesting. My mp3 player clearly prefers Bruce Springsteen.
How do you feel about shuffled playlists?
Punk Rock Operations Research 
April 27th, 2012 at 9:50 pm
I’ve been running with Pandora, but I find it occasionally (more often than I’d like) goes off on a “female ballad” jag that isn’t very compatible with a good running pace.
I recently tried iheartradio.com using the same artist to create a station. It has generally kept a better pace, but it always starts with a song by the base artist, and it seems to have a more limited artist selection (or at least the selection evolves more slowly than Pandora’s) even though I have it set for “most variety”. One Pandora feature is that you can add artist variety to your playlist by hand. I haven’t checked to see if it can be done in iheartradio, but I haven’t spotted any obvious link to that capability.
The article you link makes some interesting observations, but having just finished teaching intro stat, I’d be interested to know if their analysis produced results that were statistically significant. (If I’d know about that before, I might have used it in class.)
May 3rd, 2012 at 4:06 pm
My personal preference is a random permutation of a fixed playlist (which stops when finished) — it seems to be more of the norm due to the guaranteed lack of repeats.
Also, from the linked Cnet article (circa 2007):
“We then used the Smart Playlist feature to force iTunes to make random playlists 25 and 40 songs long, respectively. Ten playlists of each length were created, providing a total of 20 playlists and 650 possible song positions.”
10 playlists of size 25, 10 of size 40… sounds like they should/could have increased that sample size a bit!
May 3rd, 2012 at 4:09 pm
@Matthew, I wondered the same thing about statistical significance! Maybe I should assign a random playlist project next time I teach intro stat.
I like the variability in Pandora. I stopped listening to music about 7.5 years ago when my first daughter was born. Pandora has taught my about new music. When I discover a song that I like elsewhere, I manually add it to my “new music” station.
My kids have a Pandora station, and it’s hard to tune it. They just want popular music that is fun to dance to. Much like the ballad streaks during your runs, Pandora’s algorithm doesn’t identify good dancing music suitable for 4-7 year olds. Pandora once played the same song twice in a row for them (!)