The authors analyzed 7-day, 14-day and 21-day windows following the game. They found increased COVID spikes in 14-day and 21-day windows (although not 7-day windows). So I would guess one possible policy in the future would be to test for windows at varying intervals after the first game, and see if there is a spike before deciding on the second game. Since NFL games are weekly (for the most part), not having back-to-back home games seems like a good idea. A Thursday home game right after a Sunday home game seems like a very poor idea as well.

> Overall, 269 total NFL games (117 with fans and 152 without fans) were included; a total of XX individuals attended.

Is "XX" supposed be a number here?

> When the National Football League (NFL) announced its intentions to play a full season of football in 2020, some thought the decision was devoid of consideration of the health and well-being of the players, coaches, staff members, and even the fans who would attend. However, others wanted live football back as the games would offer a respite from the stress and anxiety that the COVID-19 pandemic had brought to their lives. The NFL, like other professional sport leagues, was dealing with large revenue-based financial losses and a desire to resume play.

Off-topic, but I appreciate how we're not even pretending that the NFL was motivated by anything other than money.