Yesterday, I wrote a detailed article about the new formula I’m using to quantify the overall quality of albums in my iTunes library. It’s been working for me, but I realized that everyone rates their music differently. Webomatica, for example, explains in the comments that his song ratings are relative to other songs by the same artist.

So I’d like to explain the thought process that goes into my rating system. I’ve been using the same star rating criteria for years and that system has gone a long way toward helping me maintain control over my sprawling library. It allows me to quickly construct playlists of quality music, which is the single largest goal I have when managing and utilizing my library.

When thinking about a song’s rating, I basically need it answer one question: How likely I am to want to hear this song again? They are not designed to attribute a greater cultural value to a song, though the song’s general artistic worth plays a large role in the rating it receives. I’m more likely to enjoy a high-quality song and thus want to listen to it more often.

The rating is essentially a weighted vote for helping me determine how often a particular song gets played in the future. The breakdown looks like this:

Rating: 5 stars: This song is excellent. It shows poise and craftsmanship and I’m pretty much guaranteed to enjoy this one the next time.

Rating: 4 stars: This song is very good. Well done and not off-putting, I’ll most likely enjoy this again, but it’s not brilliant enough to be a 5. The majority of songs in my library fall into this rating.

Rating: 3 stars: This song is good. I’m not going to go out of my way to hear this one, but if I’m listening to an album beginning-to-end, I won’t skip it.

Rating: 2 stars: This song wasn’t very good. I’m fairly certain I’ll never want to hear it again. These songs are candidates for deletion. If any song stays at 2 stars for long enough, it is either upgraded to 3 stars or removed from the library.

Rating: 1 star: Not used for rating purposes. Instead, songs that are marked with 1 star are taken out of circulation, usually because of encoding problems or bad ID3 tags. Its normal rating is returned when the problem is solved. Additionally, special audio such as comedy or spoken word is automatically given 1 star to keep it from mingling with music.

It is also worth noting that my ratings are not static. As my tastes fluctuate, I’ve been known to change them. It doesn’t happen often, but sometimes a 4 star song might become a 5. Or it could fall to a 3 if whatever aspect of the song I found appealing the last time I heard it is missing. In one extreme example, a song went from 5 to 2 stars and was subsequently deleted.

There you have it. That’s where I’m coming from as I discuss song and album ratings on this site. I’d be interested to know how other people handle ratings in their iTunes libraries?