Using Spotify follower ratio to measure artist growth and fan engagement

Andrew Thompson of Components digs into the relationship between a Spotify artist’s followers and their monthly listeners, and what the data says about how this ratio impacts artist growth and fan engagement.

Guest post by Andrew Thompson from the Chartmetric blog

Editor’s Note: Andrew Thompson is a guest How Music Charts contributor and founder of publication and research group Components. Andrew’s work first caught our attention in December 2020 when Components published a study on the geography of Bandcamp genre tags. In March 2021, Components analyzed Bandcamp sales, ultimately comparing the Bandcamp business model to the Spotify business model. The article you’re about to read was published on the Components website as well.

The downward pressure exerted on artist payouts combined with the proliferating avenues of payment to artists beyond traditional channels have placed a new, heightened emphasis on fandom. Let’s call it the fandom hypothesis. As the fandom hypothesis goes, what matters isn’t how many people are listening, it’s the nature of that listening. Are listeners passively consuming sound because artists are in playlists, or are they doing so with an intent that can be monetized through the sale of merch, performances, and all manner of extracurricular offerings?

If the fandom hypothesis is correct, listener numbers by themselves aren’t terribly instructive. Instead, one has to compare those numbers with an auxiliary metric to calculate the size of a following. In this post, we’ll dive into one particular metric: The ratio of an artist’s followers to their listeners on Spotify, which we’ll call their follower ratio (aka conversion rate on Chartmetric).

First, let’s look at this ratio compared against Spotify Popularity Index (SPI), a measurement of an artist’s stature relative to all other artists on Spotify. It’s concocted with a secret sauce that includes a number of metrics undisclosed by Spotify. The score goes from 0 to 100 (the top end of which currently only includes one artist: Justin Bieber). When measuring the median follower ratio, or conversion rate, against SPI, the result is a U-shaped curve with a high ratio for both lesser known artists and also superstars.

Without looking at every individual artist on the upper and lower ends, we can’t say with certainty why this happens, but it’s not hard to arrive at a reasonable guess: Artists just starting out have a listenership personally close to them — family, friends, people in local scenes — but these artists aren’t included in many playlists, algorithmic or otherwise. That also means they have a following that might stop listening to them but (as we’ll soon see) continue following them.

As that audience expands, their music encounters new listeners more quickly than the rate at which people follow them as they’re introduced to more and more listeners. At the higher end, something kind of similar happens: The familiarity of listeners to an artist is high (pretty much everyone listening to Ariana Grande knows who she is), and so, just as there exists an awareness of less popular artists by their listeners, a similar familiarity occurs with more popular artists.

If we look at who tops the list of the artists with a popularity score of at least 80, here’s what we get:

However, the challenge when examining any one artist at any single point in time is that this ratio is hardly static, and a high ratio can indicate different things.

To understand this, let’s look at a few individual artists. Ed Sheeran‘s follower ratio, for example, has fluctuated between about 0.6 and 1.5 in the past few years. But as we can see, that number is basically the inverse of his listenership to a pretty linear increase in followers.

This linearity in follower increases holds for nearly every artist we’ve looked at. Here’s Huey Lewis & The News:

Here’s Gunna:

The point is that looking at any given artist at a particular point in time by itself doesn’t tell us a whole lot. For an individual musician, a high ratio could be a sign of a devout following, or it could be the result of a month-old surge of new listeners that cooled off after an artist was taken out of a popular playlist, leaving them with lots of followers but not as many active listeners.

So, rather than looking at individual artists, let’s examine how follower ratio breaks down by genre in terms of the 50 highest and lowest genres by average follower ratio:

What’s notable about the results is the clustering of genres, with Metal covering most of the highest positions and various types of compositional music at the bottom. But in order to be more certain, we’ll have to control for the variable of Popularity to ensure that Metal is not simply concentrated at the high and low ends. To do that, we’ll look just at the middle band of Popularity, from 30 to 60, and rank the top and bottom 10 genres for each bin of Popularity (measured in increments of 10), scanning among the most common 150 genres in each bin:

Of the Top 10 genres by median follower ratio in each bin, two are Metal and the other is K-Pop, which is more or less in line with our higher-level ranking above. Similarly, compositional music dominates the bottom ranks.

So, Metal and K-Pop artists have the most devout fanbases, and Hollywood composers the least, right? Possibly.

On the one hand, both genres have reputations for attracting genuinely fanatical audiences. The Seoul Pop machine produces groups that command religious devotion from fans, and K-Pop has itself provided something of a prototype for the music industry writ large when it comes to cultivating not just listeners, but followers whose every relational facet to the group can be monetized.

Metal, meanwhile, is at least in part a genre whose identity is rooted in its explicit distinction from other kinds of Rock. Like a precursor to Noise scenes, it is sonically exclusionary, filtering out those who recoil and fostering a sense of coherence among those who don’t. The notorious history of the Norwegian Black Metal scene, whose members operated on par with a death cult, is less an inexplicable exception to the rule than the rule’s reductio ad absurdum made manifest.

On the flip side of the chart, the results track for two primary reasons. First, it makes sense that people are less interested in listening to Hans Zimmer than they are to the Inception soundtrack. Additionally, contemporary Classical music notwithstanding, the Classical canon is generally composed of the deceased. New releases tend to come in the form of new renditions of existing compositions by different symphonies, quartets, and so on. The nature of “following” is different, and save for a subset of Classical listeners, less imperative.

In other words, on a genre level, the results make a degree of intuitive sense. However, this doesn’t mean that one can apply the results willy-nilly to any given artist. As an example, here’s the ratio, followers, and listeners for the K-Pop group Imfact:

Remember, follower growth curves for artists are almost universally positive and linear. That holds true even for artists that aren’t gaining listeners. In the case of Imfact, despite having an almost completely flat number of listeners over the past year, people continue following the group. Are K-Pop listeners more likely to indiscriminately follow every artist in the genre? Are Metal fans more likely to follow artists and then listen to their music off Spotify altogether, whether on vinyl or elsewhere?

On a practical level, this all ultimately means that while certain genres are more or less likely than others to command followings, a high metric in and of itself isn’t indicative of an engaged fandom or a successfully “converted” listenership, and the only thing we can say for near certain is that there is something distinct about follower ratios for particular genres. It’s also possible that monitoring follower ratios over time for artists that fall roughly within the range of 20-70 SPI could reveal something about how successfully these “middle-class” artists are converting listeners into fans. However, these possibilities yield more questions than definitive answers, opening up even more avenues for inquiry.

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