A lot of different things could happen in the N.F.L. conference championship games on Sunday.

But oddsmakers are pretty sure what is likely to happen. The New England Patriots will beat the Pittsburgh Steelers by about 6, and the Atlanta Falcons will defeat the Green Bay Packers by 4 or 5 in a high-scoring affair.

One of the truisms of gambling is that it is difficult for a team to be a great bet week in and week out. That’s because the more a team wins and covers the spread, the higher its spread will be the next week and the week after that. Eventually, most teams congregate close to .500 against the spread for the season.

That makes this season for the Patriots all the more remarkable. Despite being favored in 15 of 16 games by as many as 17 points, the Patriots finished 13-3 against the spread, earning a tidy profit for those who bet them blindly. That was the best record in the league.