It has long been speculated that Super Bowl ratings aren’t accurate because they don’t take into account the number of people watching the game at parties and bars.

A case in point could be in looking at my town’s rating for Sunday’s Super Bowl.

The game did a 54.9 rating in Chicago; 1 local ratings point is worth nearly 35,000 homes. That was nearly five points higher than the 50.2 local rating for the 2007 Bears-Indianapolis Super Bowl.

Now how is it possible a Chicago rating for a Bears Super Bowl could be lower (by 166,000 homes, no less) than a game featuring one team from the East Coast and the other from the West? Answer: It is highly unlikely.

Here’s a theory:

In 2007, there were countless parties and mass gatherings at bars with multitudes of Bears fans watching the big game throughout the Chicago area. Those viewers are not counted in the final rating since Nielsen bases the number on people watching in their homes. The actual rating had to be much, much higher than 50.2.

Fast forward to Sunday. A huge storm hits the area. Parties are cancelled; people don’t go to bars. Instead, they stay in to watch the game. Nielsen registers those homes, and voila, the rating is larger for a non-Bear Super Bowl.

Look no further than Chicago registering a 44.8 rating for Super Bowl 48 in 2014. While this year’s game was much better, it wasn’t more than 10 ratings points better.

The Chicago dynamic seems to support the long-time contention by the networks about the Super Bowl rating being too low. Richard Sandomir addressed the issue in a story in the New York Times Saturday.

“I really believe that the number is underreported substantially,” said NBC Sports chairman Mark Lazarus during a news media conference call. “If you take 120 million or so and add the parties, there’s no doubt in my mind that one in every two Americans is watching the game.”

Alan Wurtzel, president of research and media development for NBC Universal, talked about the impact of out-of-home viewing.

“Nielsen has said that their methodology was designed to deal with in-home viewing, not out-of-home,” Wurtzel said in the New York Times story. “The issue now is that as the medium has become more portable and the technology more personal, it isn’t about people watching at the health club or bar, but on a smartphone or tablet. And we know this behavior is only increasing. It will be the new normal, and we have to account for it.”

Expect NBC to examine what happened with Chicago viewers Sunday.