There are several factors that make up the final football odds, factors that the NFL odds makers take into account. And contrary to popular myth and opinion, these NFL odds factors are not as much based on the merits and abilities of the teams but on how the mass gambling public will perceive and act upon those factors.
NFL odds start with the home field advantage. Because the masses do place such an emphasis on home field, the NFL odds makers must also take that into account, which often ends up driving the price up on the home teams into “overlay” status, which means that many times home teams are favored by more than they actually should be in NFL odds.
Another factor that often gets more consideration from the public than is truly merited is injuries. Nothing makes the NFL odds move like an earthquake than the announcement of a key player particularly a quarterback, being injured and listed as “out” for that team's upcoming game. Oftentimes, however, the football odds will move out of proportion to where it truly belongs because of the mainstream betting masses overreaction to and resulting wagers because of that injury.
Another football odds pointspread factor that can alter the line out of balance from where it truly should be is the results from a team's previous game. Let's say, for example, that a team expected to have a bad season ends up winning their opening game in big fashion versus the NFL odds. The public will react to that result and start to get too clever and smart for itself and think that they have discovered a “sleeper” and “surprise” team that is going to roll versus the NFL odds. The NFL odds makers will, of course, adjust the line with that in mind, taking away that team's board value. The opposite affect can happen to a strong team that stumbles out of the gate versus football odds.
Keep some of these things in mind as you look at the NFL odds this season.