Last month Animal Crossing: New Horizons set records as the fastest-selling title in the Animal Crossing franchise in both Japan and the UK, a stunning achievement that might have left me more impressed if Pokémon Sword and Shield had not accomplished the very same thing just a few months earlier. These “record-breaking” moments have become commonplace for Nintendo’s first-party Switch sales, which continue to snowball when compared to previous generations. After having read similar sensational headlines regarding The Legend of Zelda: Breath of the Wild, Super Mario Odyssey, Super Smash Bros Ultimate, and many others, I started to wonder what it was about the Switch that seemed to be causing a noticeable “spike” in Nintendo game sales.

At first, it may be easy to dismiss these repeated anomalies as inevitable happenstance. The Switch is one of Nintendo’s better-selling hardware devices, the gaming industry continues to grow each year, and the games themselves are oftentimes unrivaled in their quality. These facts alone paint the picture of a console that should probably be breaking records. However, Nintendo has undeniably crafted high-quality titles, grown the gaming population, and fostered player bases that surpassed 100 million in the past, so why does it seem like first-party IPs are attracting so much more attention on the Switch? Are the core fanbases for Nintendo’s legendary franchises legitimately growing or is it business as usual for a successful Nintendo console?

Below will be references to a multitude of sales data and calculations. You can find all of the sources and math here.

In a vacuum, bombastic sales numbers such as Super Mario Odyssey’s cool 15.69 million units on the Switch appear to unquestionably trounce Super Mario 3D World’s 5.83 million on the Wii U. It’s unfair to make the claim, however, that 3D Mario is more popular today than it was throughout the previous generation with this data alone. The Switch has over four times the amount of potential buyers than the Wii U (52.48 million VS 13.56 million). So even if Nintendo decided to hand out a free version of Super Mario 3D World with the purchase of every Wii U, the game would still have lower numbers than Super Mario Odyssey. Super Mario 3D World’s final sales data says nothing about the franchise’s overall popularity and everything about the failures of the Wii U to attract a reasonably sized audience.

Instead, I want to focus on the percentage of players who own Nintendo games on a per console basis (known as a game’s “attach rate”). Attach rates are not data above reproach, but they can be used as a general indicator for how interested a player base is in a specific game. Super Mario 3D World may have had worse overall sales, but it boasts a monstrous 43% attach rate on the Wii U compared to Super Mario Odyssey’s 30% on the Switch. If Super Mario Odyssey’s sales numbers gave the appearance of extreme franchise growth, then its 13% decrease in attach rate appears to tell the opposite story. What happens when we add the rest of the 3D Mario series into our attach rate comparison?

By taking the average attach rate of Super Mario 64, Super Mario Sunshine, Super Mario Galaxy, Super Mario Galaxy 2 and Super Mario 3D World, we wind up with a pre-Switch franchise norm of 25.6%. On average, 25.6% of a Nintendo console’s player base decided to purchase a 3D Mario game before this current generation. Considering that Super Mario Odyssey is currently holding steady at 31%, we can finally say that there is some evidence that the Switch audience is more invested in 3D Mario than average. As you might expect, running this experiment against some of the top-selling Nintendo games on the Switch shows similar results:

You'll find the exact numbers and calculations here.

The positive spike in attach rates is more extreme in some cases than others. Regardless, the current data suggest that the Switch is attracting a greater cumulative interest across Nintendo’s first-party titles. In particular, the Switch installments for the Zelda and Pokémon franchises are beating their respective average attach rate by a wide margin. 10% of NES owners bought The Legend of Zelda while a franchise-high 31% of the Switch’s audience purchased The Legend of Zelda: Breath of the Wild. Has the Zelda audience (and the audiences for other major Nintendo franchises) really grown that significantly throughout the Switch generation as the data suggests?

Maybe. Although it is true that a higher overall percentage of Switch owners are buying first-party games, attach rates can inflate due to factors that don’t necessarily imply a growing audience. This misdirection is conveniently shown by Nintendo’s previous home console.

You'll find the exact numbers and calculations here.

As seen in the chart above, before there was a “Switch Spike,” there was a “Wii U Spike.” Most notably, Mario Kart 8 celebrated a jaw-dropping 62% attach rate on the Wii U. An attach rate that high is practically unheard of as it implies that more than half of the entire Wii U audience purchased Mario Kart 8. Unfortunately, the Wii U’s success in attach rates was a result of the console’s inability to attract a diverse audience to begin with. If you want to know more about how that happened, you can read about it in my editorial on the topic, but the short version is that by trying to please everybody, the Wii U pleased almost nobody. Nintendo couldn’t convince the casual gamers of the previous generation nor the Sony/Microsoft fans to make the switch.

The audience that remained were the Nintendo faithful. These passionate fans didn’t need the latest third-party release or a mass appealing twist on gaming entertainment to purchase a Nintendo console. They bought a Wii U for Mario, Zelda, and Smash. What the Wii U shows is that a game’s attach rate only tells one side of the story. A console also needs to attract a relatively large and diverse sample size to determine how much audience growth is happening within these franchises.

Thankfully, we can see this phenomenon of full display with one of Nintendo’s other consoles. At 101.63 million units, the Nintendo Wii outperformed the Wii U by a factor of seven. The Wii was able to become one of the best selling gaming consoles in history by growing a mass-market audience. Nintendo’s motto at the time was “expanding the gaming population,” and they achieved this by combining their innovative hardware design with new broad appealing franchises.

You'll find the exact numbers and calculations here.

A similar attach rate comparison for first-party content on the Wii paints a uniquely different picture than the Switch and Wii U. Nintendo’s new and most casual-friendly franchises demonstrated impressive attach rate percentages. At the same time, the company’s legacy brands suffered. Super Mario Galaxy weathered an almost 20% drop after coming off from the comparatively popular Super Mario 64 and Super Mario Sunshine. By having high attach rates that defy expectations as well as booming console sales, the Wii data suggests an audience with a growing interest in first-party content. It just happened to be a different kind of first-party content than we typically expect from Nintendo.

The Wii demonstrated how to grow population interest while the Wii U highlighted what it looks like to have high investment in Nintendo’s traditional first-party content. Like Goldilocks, the Switch appears to be doing a little bit of both. Similar to the Wii U, the Switch is destroying average attach rates for long-established franchises like Zelda, Pokémon, and Smash. Like the Wii, the Switch is one of Nintendo’s fastest-selling hardware devices and is on track to potentially dethrone the Wii in becoming the company’s best-selling home console of all time.

In a way, the Switch seems to have adopted a modified version of the “expanding the gaming population” motto. Instead of “expanding the gaming population,” Nintendo is “expanding the core gaming population.” Instead of introducing new franchises to attract new people, the Switch is reintroducing old franchises to attract new people.