How Random is iPod's Shuffle?
Does your iPod keep playing the same tune over and over again when left on shuffle? Does it grant way more air-time to, say, Bruce Springsteen than to Emmylou Harris?
Many people report that when they let their iPod choose, it plays its own favorites. Shuffle play doesn't appear at all random.
The questionable randomness of shuffling iPods led a trio of statisticians from American universities to mathematically assess whether the iPod's shuffle feature truly selects tunes randomly.
To probe Apple iPod behavior, the researchers developed probability models and collected tune-playing data from iPods.
Despite the investigation's thoroughness, it failed to find evidence of iPods shuffling in non-random ways.
So the stack of songs your iPod last shuffled through was selected purely by chance. And no-one knows when it will play those tunes again.
Amy G. Froelich, William M. Duckworth and Jessica Culhane. 2009. Does Your iPod Really Play Favorites? The American Statistician. 63(3): 263-268.