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I just calculated an HHI index for HRPF from 2010 to (extrapolated) 2026, because why NOT be a nerd about it. I figured other people would find it interesting.

Okay this dataset is from @unwandering11 who scraped pairing data for pairings that met either criteria:

in the top 10 ships in at least one year and more than 100 fics total

>300 fics total (this actually only adds sidnate, I believe, the first filter captures everything else).

That gives a list of 42 pairings. (I forget how she handled multi-pairing fic, FYI, but will check when she's back online. I *think* she assigned fic to the first pairing listed.)

You can really see the explosion of willmack BUT also how non-willmack HRPF is surging in the last few years (note we normalized 2026 data, extrapolating to a full year for the partial year of ~5 months of data):

So basically: willmack is a separate phenomenon. It's new fic/new writers, not (exclusively) writers from other HRPF pairings switching to willmack, and the rest of HRPF is growing faster than ever (since early AO3 days).

For fun, I calculated an approximate HHI (Herfindahl-Hirschman Index), which is a competitiveness metric. The lower the value, the more "competitive" a market is; in this case, the lower the value, the more diverse the HRPF fic offerings are by pairing (less domination by one or a handful of pairings):

The 753 in 2014 is when Kane/Toews (20.5%) & Sid/Geno (14.8%), with some Bennguin (9.3%), were the dominant pairings. Those three pairings made up~45% of HRPF fic in 2014.

The little peak of 493 in 2018 is due to a bit of a resurgence of Sidgeno (17%) and the rise of Matthews/Marner (9.2%), but you have to add the next three pairings to get up to the 45% mark (Bennguin, Ovi/Backstrom, Kane/Toews, in order).

After that the pairing diversity of the fandom really increases to 2022 as the HHI bottoms out. The rise of the HHI in 2025 and then extrapolated to 2026 is all willmack becoming the most dominant pairing. It was 16.4% of fic published in 2025, and is extrapolated to be a whopping 35% of fic published in 2026. 🤯 (The HHI label in 2026 didn't export for some reason but it's 1296.)

Without willmack, however, HRPF is more pairing-diverse than ever, with no other pairing cracking 5% (Sidgeno is 4.5%, and then Jack/Nico is all the way down at 2.2% for our extrapolated 2026 dataset).

There really are two different fandoms inside HRPF right now: willmack, and everybody else. I'm not in willmack at all and only have a couple people who put it on my dash (hi @hokeypuck), but I feel like that checks out. 😅

Sorry for giving data in pictures, idk how to do tables in tumblr.

Resurrecting my tumblr because PWHL Reddit said PWHLblr was the place to be.