In part 1 of this series looking at artist metrics on Last.FM, I talked about PPL (Plays Per Listener) and also the relative popularity of each act’s top track.
In this part we dig a little bit deeper into an artist’s catalogue, with two more metrics based on their list of top tracks (which, remember, are the tracks with most listeners over the last six months, not over the whole of LFM’s history). I’m calling these metrics – rather unimaginatively – head and body. “Head” is the number of listeners to the tenth most popular track expressed as a percentage of the number of listeners to the first. “Body” is the number of listeners to the fiftieth most popular track expressed as a percentage of the number of listeners to the tenth.
Both of these are based on the same principle – ratios of popular and less popular songs in an artist’s catalogue – but they turn out to measure quite different things. Head measures the extent to which an act is a several-hit wonder. A high head means that your top track isn’t that much more popular than your tenth, which usually means you’ve racked up either a bunch of successful singles or have at least one album that people are keen to listen to in toto. A low head means that you have a few, or maybe just one track which people are particularly keen on but that interest doesn’t extend very far – it suggests a big chunk of casual listeners in your audience.