Fan bases are always out to compare themselves, and it really is entirely subjective. Plenty of San Francisco 49ers will proclaim this fanbase No. 1. Of course, other fans, and even some 49ers fans will point to the "Whiners" nickname. It is all subjective jibber-jabber, but it can be amusing chatter.
Someone decided to put a little more thought into ranking fan bases. More thought does not mean the ranks are necessarily better, but it is at least a little more useful than drawing teams from a hat. Someone at Emory University put together a study to try and determine "fan equity" as a way of ranking the "best" fans in the NFL. They used a revenue premium model involving the following:
In terms of the nuts and bolts of what we are about to present, we use fifteen years of data on NFL team performance, ticket prices, market populations, median incomes, won-loss records and multiple other factors. We create statistical models of box office revenue, and then see which teams over- and under- perform the model's predictions.
You can read more details on their model here.
The 49ers rank 10th on this list. The teams ahead of them include:
The authors acknowledge this is primarily a revenue model. Teams selling out new stadiums that are charging more for their tickets are going to do better than teams that sell out older stadiums. While this does measure the amount a "fan" has to invest to continue going to games, it is not really measuring fandom in my mind. It helps measure the popularity of a team, but it does not mean the people going are necessarily hard core fans.
When you are charging high five figures for a stadium builders license, and then another sizable chunk for the cost of the seats, you are going to sometimes get corporations purchasing seats and suites. They can take clients to games and they can reward employees, among other things. Some of the people going are serious fans of the team, but there is also the crowd that is going to be seen. People that are going to show up, chill in the lounge and make their way out from time to time. The company is coughing up the money, so anybody is entitled to do what they want, but let's not pretend paying big money is indicative of a stronger fan base.
Around the rest of the NFC West, the Arizona Cardinals rank No. 19, the St. Louis Rams rank No. 23 and the Seattle Seahawks rank No. 26. This seems a bit odd, but here is what they say about the Seahawks:
For example in our NFL rankings Seattle has tended to perform poorly. This result has created many questions about the rankings. The numbers suggest that while the Seahawks fans may be very loud, they are a below average fan base on the Fan Equity metric. At the end of the day, it appears that Seahawks fans are not willing to pay the prices that you would expect for a team of the quality of the Seahawks in a market with the demographics of Seattle. However, there is another explanation for the Seahawks fans' poor showing. Maybe the assumption that the Seahawks are pricing to maximize revenues isn't correct. Of course, what this would really boil down to is whether the Seahawks owners are more altruistic than other NFL owners. Perhaps?
The rankings do not take into account how fans travel on the road, and it does not factor in merchandise purchasing. Both involve data that is harder to acquire than home ticket prices and attendance figures. I'd be much more curious to see a study that factors in those kinds of things given that they add a better understanding of a given fan base.