Attendance - 50% of the Fan Base score

Average home league attendance per season from 1980–81 to 2024–25 (45 seasons), expressed as a percentage of the #1 club in each season and then averaged across seasons. Each season is weighted equally - so no recency bias. The COVID seasons (2019/20, 2020/21, 2021/22) are discounted.

Social media - 50% of the Fan Base score

Total followers across YouTube, Instagram, Facebook, X and TikTok, summed across all official club accounts starting from 2023. As with Attendance, values expressed as a percentage of the #1 club in each season and then averaged across seasons, with each season weighted equally.

Data sources for attendance

Transfermarkt is the single authoritative source covering roughly 75% of all info, and naturally this has strong coverage of the big clubs. The remaining ~25% are filled using, in order of preference: (1) linear interpolation between adjacent known years; (2) league-trend × club-scale modelling; (3) external-knowledge baselines where verified data is sparse (e.g. pre-1989 Argentina during the hyperinflation crisis); (4) single-club-country direct baselines (Georgia, Slovakia, Ecuador, where the club essentially is the league); (5) specific historical overrides for known facts - for example, Aberdeen 1982–83 = 19,500 as Cup Winners' Cup winners under Ferguson; a +18% continental-trophy boost in CL or Libertadores winning years, +12% afterglow the following season, +5–10% for finalists, +10% for Europa / Sudamericana / CAF / AFC CL winners; stadium-renovation adjustments (e.g. Maracanã 2010–12 reducing Flamengo and Fluminense attendances by ~35%); and war / political-shock adjustments (Croatian War 1991–95, Yugoslav UN sanctions 1992–95, Argentine 1989–91 hyperinflation, NASL collapse 1984 affecting US clubs).

Data sources for social media

CIES for the top c.100 clubs, and then individually sourced for each of the smaller clubs directly from the 5 social media platforms.

Attendance is relatively balanced - yes, the likes of the Camp Nou, Old Trafford and Dortmund's Signal Iduna Park draw giant crowds - but any club that fills 50,000 seats week in, week out stays within touching distance of the giants.

Social media is the opposite: brutally lopsided. Real Madrid and Barcelona are in a league of their own, with even the big Premier League or Italian clubs not within half of their numbers. And the top ten clubs between them have more followers than the rest of world football combined. If you want a single measure of true global pull today, social media is probably it.

Its also worth calling out the reality of the modern game -  the former giants like Ajax, Boca Juniors and River Plate are rounding errors in global pull compared to the big boys . . . which filters down into financial power, thus better players, more trophies etc etc.

And fair play to the likes of Celtic, Rangers, Stuttgart, Schalke, Real Betis, and in particular some of the Mexican Clubs. They are some outrageous attendances compared to the other measures of success.