is the Pandora algorthm broken

[Janx]

for folks interested in how stuff works...

Pandora.com uses the music genome project's data to identify traits in songs. These traits are then matched up, so that when you say you like Manowar, they can play other songs with similar traits.

Here's the deal, in data, trait matching is a 2 way street. If you look for all items that have the same trait(s) as A and get B, then when you do the same thing for B, you should get A in the result set.

there are some exceptions to that, but as a general observational rule of how data and querying works....

So I made a Manowar channel to hear other bands like Manowar. they give me Iron Maiden, Dio, and Sabaton. Sabaton is new to my ears, so I made a new channel for Sabaton.

With Sabaton, I don't hear Iron Maiden, Dio, or Manowar, and instead hear other new bands like Edguy and Hammerfall.

the result set for either channel is such that I could list all the bands that appear (meaning it's is rather short and finite, rather than broad).

I find it odd, because I would expect that if Sabaton is "like" Manowar, then I should see a Manowar song crop up in the Sabaton list because at least one song from either band has like traits to the other.

Let's just say I've done extensive testing on this...

What I'm finding is you'll get about 8-20 bands that show up in a channel, and after a few days of listening, you generally won't hear any new songs, just repeats.

Obviously, I could add more bands to the channel to broaden it's mix, but given the commonality 2 bands have, elements of both bands should cause more variety.

There's something restrictive in Pandora's filtering that is not obvious, and thus limiting result sets.

 

[El Mahdi]

Providing feedback (thumbs up, thumbs down, skips, etc.) can help define a station for you, but I don't think what you're describing means the algorithm is broken. Pandora isn't only about making a station that you want to listen to, it's also trying to narrow down music that you will buy. It's as much a marketing device as it is an entertainment service...or maybe even more of a marketing device than the latter. So, part of it's "algorithm" is finding music you want to buy and selling you on it.

 

[Dannyalcatraz]

Yes, it's broken, and needs to be nerfed.






What?

Yeah, stuff like this is imperfect, but improving. I don't know that it will ever match humans' abilities, but it may get so close that it doesn't matter.

 

[jonesy]

Providing feedback (thumbs up, thumbs down, skips, etc.) can help define a station for you, but I don't think what you're describing means the algorithm is broken. Pandora isn't only about making a station that you want to listen to, it's also trying to narrow down music that you will buy. It's as much a marketing device as it is an entertainment service...or maybe even more of a marketing device than the latter. So, part of it's "algorithm" is finding music you want to buy and selling you on it.

But then it should work both ways the way Janx is describing. So it is broken.

 

[Starman]

Pandora does make some funky selections sometimes. I created a Meat Loaf station and the second song it played was from Dragonforce. I happen to like cheesy power metal including Dragonforce, but I can't say that I expected that band to pop up on a station that started with Meat Loaf. I have found that for the most part with a bit of tuning I can get some really good stations, though.

 

[El Mahdi]

But then it should work both ways the way Janx is describing. So it is broken.

May be I didn't word it very well.

The Pandora algorithm isn't just about a collection of music that goes together for your entertainment, the algorithm is also trying to serve the needs of those that founded it and support it...namely companies that sell music. It may not make sense to each person, but one of it's dual purposes (or perhaps even it's primary purpose) is to get you to buy music you don't already have, but limited to specific feels or genres you might like (thereby increasing the chances you might buy something...i.e.: targeted marketing). That's why it ends up repeating some of the same music over and over, and seems to have a limited amount of variety in a chosen channel. Instead of expanding options, the marketing aspect limits options...limiting to choices you're most likely to buy.

In that respect, it's not broken. It's doing exactly what the designers want it to do.

 

[The Red King]

Perhaps that this is the way they want it?

You like Ban A, that exposes you to Band B, who expose you to Band C. This way your choices will never form a closed loop.

It is meant to keep you looking and eventually buying.

 

[CAFRedblade]

It's probably a design feature, not a flaw, with the intention to introduce you to more/new music in a similar style to the band/musician you already like.

The more varied a selection, the larger the number of musicians music get played, and paid(hopefully).

Plus, most of these systems allow users to further customize their playlists, which should help you narrow back to specific bands/musicians you already like if you wish.

 

[GSHamster]

I do see [MENTION=8835]Janx[/MENTION]'s point. If A is similar to B, then B should be similar to A. For example, let's define musical similarity as a spectrum:

A - B - C - D - E

This means that C is closer to B than to A. If we say that Pandora should show music within one degree of similarity, then starting with A should give you a channel with A and B.

And you would expect that starting with B gives you A,B,C. But if you only get B,C, then that means that the algorithm is biased in one direction.

My first thought would be that maybe the channels are not independent. I would get a friend with a Pandora account. You start with song A, and he starts with song B. Pandora might be looking at your existing channels when branching out.

 

[Fast Learner]

Understand that if you start a channel based on one or more bands instead of on specific songs, you may not get the matches you'd expect since specifying band means the algorithm has to try to find things that are similar about the majority of a band's songs. Consider this:

Band A has 10 albums with a total of 100 songs. Among those songs, 80 of them have characteristics that match Sound Set Red (a certain set of common characteristics) and the rest have other sounds.

Band B has 10 albums with a total of 100 songs. Among those songs, 20 of them have characteristics that match Sound Set Red and the other 80 match Sound Set Blue.

You start a channel with Band A and Pandora throws in some of the 20 Band B songs that have Sound Set Red characteristics because it's looking for songs that are similar to Sound Set Red.

Then you start a channel with Band B and you don't end up hearing any Band A songs. Not surprising, since Band B has so few Sound Set Red songs. Instead you end up hearing Sound Set Blue songs, which may be somewhat similar to Sound Set Red, but not close enough to kick in many or even any Band A songs.

If you instead started a new channel with the specific Band B Sound Set Red songs you heard on the first channel and not Band B in general, you'd hear Band A songs in the mix.