There are endless ways to rank NFL teams. Opinion polls are one option, but they vary wildly from site to site and even writer to writer. That's how the Bills can end up at No. 15 on the ESPN and Yahoo power rankings in the same week USA Today called them the No. 3 overall team. A lot of it is guessing. 
So we thought it would be interesting to try and take a little of the guesswork out. We took our proprietary ranking algorithm, the same one we've used for years to predict tournament results in the college sports world, and applied it to the NFL. The results have been interesting so far.[divider]
How Our NFL Power Rankings are Calculated
If you're a college basketball fan, you're probably familiar with the Rating Percentage Index (RPI) the NCAA tournament selection committee uses to help select and seed the field for their tournament. It's pretty straightforward — a simple combination of winning percentage (50%), opponents' winning percentage (25%), and opponents' opponents' winning percentage (25%).
RELATED: College Football Rankings
Our system is similar to the RPI, except instead of wins and losses, we use adjusted margin of victory as the focus statistic. This provides more granularity to our data. The "adjustments" we make to each team's aggregate margin of victory account for home field advantage, and slightly reduce the impact of blowout wins (or losses).
From there, we combine a team's adjusted margin of victory with their opponents' rankings and run all the numbers through the computer several times — what's known as an "iterated function" — and it spits out the list.
Games are given slightly more weight each week, to account for momentum, and there you have it. Predictive, objective, data-driven NFL power rankings.
Some of these seemed a little off to me, so I added comments when necessary. It'll be interesting to see how these evolve over the course of the season. [divider]
NFL Power Rankings (Week 5)
1. Kansas City Chiefs (4-0)
This feels right. The only undefeated team in the NFL has scored at least 24 points in every game so far, and the offense leads the league in yards per play average with a robust 6.8.
2. Denver Broncos (3-1)
Oh boy, the computer spit out our first surprise of the day and we're only at No. 2. The Denver Broncos' defense has been otherworldly this season, allowing just 2.4 yards per rush against the likes of Ezekiel Elliot, LeSean McCoy, Marshawn Lynch, and Melvin Gordon, but the offense has left something to be desired. Second overall feels a little high to me.
3. Buffalo Bills (3-1)
Looks like our computer agrees more with Yahoo than with ESPN and USA Today, and after watching the Bills' defense frustrate Atlanta at home Sunday it kind of makes sense. Even if you remove the questionable call on the Matt Ryan fumble, the Falcons didn't look like themselves. Buffalo held Atlanta to under 20 points for just the second time since 2015.
4. Washington Redskins (2-2)
One thing that's pretty easy to see about our computer: it doesn't care about "pedigree". It's only interested in results, and Washington has produced decent results against a tough schedule so far this season. They are 2-2 against a schedule featuring four teams ranked in the top half of the league and three teams ranked in the top ten. Pro Football Reference's strength of schedule metric has the 'Skins with the toughest schedule in the league.
5. Philadelphia Eagles (3-1)
Eagles fans will not be pleased to see their team ranked one spot below Washington, a team they already beat, but that has everything to do with strength of schedule and margin of victory. The three games Philly has played since their Week 1 win at Washington have been extremely tight.
6. New England Patriots (2-2)
While the Patriots haven't looked great by their lofty standards, they're still 2-2, and feature the second best scoring offense in the league. They have played the second toughest schedule in the league according to Pro Football Reference, so as long as they do a better job not leaving receivers WIDE open, they will be fine.
7. Oakland Raiders (2-2)
It's been a weird start for a team many picked as a darkhorse Super Bowl contender this year, and it's ony going to get weirder now that Derek Carr is set to two-to-six weeks with a transverse process fracture in his back.
8. New Orleans Saints (2-2)
Another surprise. But did you know that the Saints' defense has allowed only one more point than the Seahawks' this season? A lot of that has to do with the Miami shutout, but it wouldn't be difficult to argue that the Saints are right were we expected them to be coming into the season. Especially after a tough Minnesota/New England back to back to start the year.
9. Carolina Panthers (3-1)
The win over New England was big, but didn't count for quite as much as it might have in years past, when the Pats would have been right at the top of this chart. Even so, the Panthers' defense has been solid, allowing just 70 points so far. If they can increase their turnover margin (just two turnovers forced this year), watch out.
10. Atlanta Falcons (3-1)
Atlanta fans feel like a bad call stole a game from them this weekend. Matt Ryan's arm was moving forward on what the refs called a fumble, which the Bills returned for a touchdown. But still, the Falcons had plenty of chances to win that one, including the final minute. Their defense needs to force some turnovers of their own if they are to move up this list.
11. Detroit Lions (3-1)
The Lions' defense ranks in the bottom half of the league in yards allowed per play, a pretty standard measure of defensive quality, but their saving grace has been turnovers. Detroit has turned a league-high 11 turnovers into a top-five scoring defense, allowing just 17.5 points per game. The Lions only forced 14 turnovers all of last season.
12. Jacksonville Jaguars (2-2)
Who is this team? The Jaguars schedule features two blowout wins, a blowout loss, and an overtime loss to the New York Jets. They find themselves this high in our rankings because the computer just can't figure them out.
13. Houston Texans (2-2)
How about that Deshaun Watson kid, huh? His athleticism and decision-making have improved every facet of what was an absolutely anemic offense last season. The defense hasn't been as good as we expected, but the potential is there for this whole thing to come together in Houston.
14. Minnesota Vikings (2-2)
Knee injuries are killing the Vikings. First Teddy Bridgewater, then Sam Bradford, now rookie sensation Dalvin Cook. The Minnesota defense has been outstanding, but injuries have cast a shadow on what was a very promising start for the Vikings.
15. Green Bay Packers (3-1)
It's been a confusing season for Green Bay. After a convincing win over a questionable Seattle team and a loss at Atlanta, they very nearly (and probably should have) lost to Cincinnati at home. Nothing like a comfortable home win over the hapless Bears to take the all-time lead in the series to right the ship.
16. Los Angeles Rams (3-1)
After four weeks the Los Angeles Rams have the number one scoring offense in the league, and it's getting tougher to call this a fluke. Jared Goff has looked more like a worthy No. 1 overall pick than he did a season ago, and the Rams are in sole possession of the NFC West lead.
17. Los Angeles Chargers (0-4)
Things are not going well in Los Angeles. Not for the Chargers at least. They are one of four winless teams in the league at this point. If there's any silver lining here, it's this: of the 139 teams that have started a season 0-4 since the merger, only the 1992 Chargers have gone on to make the playoffs.
18. New York Jets (2-2)
The two New York teams have combined for two wins this season, and both belong to the Jets. Weird. Considering how low people were on this team starting the year, 2-2 should feel pretty good.
19. Tennessee Titans (2-2)
Things were rolling right along in Tennessee, until this weekend brought a Marcus Mariota injury and a thumping at the hands of Houston. Now the NFC South looks like anybody's division to win.
20. Tampa Bay Buccaneers (2-1)
The biggest thing working against the Bucs right now is a weak schedule — and the fact that they've only played three games. The more they get out on the field the better our system will be able to recognize how good they are.
21. Pittsburgh Steelers (3-1)
Alright these rankings suck. Right? How could a 3-1 Pittsburgh team possibly be ranked behind 0-4 San Diego? I'm asking myself the same thing.
The only thing I can point to is that the Steelers have done just okay against an extremely weak schedule so far. I assume this will be sorted out as soon as more games are played.
22. Dallas Cowboys (2-2)
The defense has been weak — allowing 35 points to the Rams and Broncos, and outside of DeMarcus Lawrence, doing very little to pressure the quarterback.
23. Seattle Seahawks (2-2)
Two quarters of great football doesn't make up for the 10 that came prior. The Seahawks are 2-2, which isn't that surprising considering the early-season trips to Green Bay and Nashville, but haven't looked good doing it. The defense that has been their calling card for years just isn't clicking yet — they rank 15th in the NFL in yards allowed per play.
24. Miami Dolphins (1-2)
The Miami pass defense has been worse than their pass offense, and that's saying something. The defense ranks third to last in opponent QBR and still haven't intercepted a pass, while the offense ranks second to last in net yards gained per pass attempt.
25. New York Giants (0-4)
What is happening here? The Giants forgot how to play offense while the defense has forced two turnovers in four games. They still have to play the Chargers, Broncos, and Seahawks before a Week 8 bye.
26. Cincinnati Bengals (1-3)
This team has all the pieces in place to be much, much better than their record shows. They could have beat Houston, they should have beat Green Bay, and then thumped the Browns. The schedule doesn't get much easier in the immediate future either — they've got the Bills this week, then head to Pittsburgh after a bye.
27. Chicago Bears (1-3)
It's time to see what the Mitchell Trubisky era in Chicago will look like. The Bears have an extra day to prepare before a Monday night showdown with Minnesota.
28. Baltimore Ravens (2-2)
If not for the league-high 11 turnovers forced by the defense, the Baltimore Ravens would be squarely at the bottom of this list. The offense has been just terrible, scoring an average of just 15 points per game. Only the Dolphins have been worse.
29. San Francisco 49ers (0-4)
The big fat zero in the W column doesn't tell the whole story for the 49ers. Three of those four losses have been by a field goal or less, and they get to travel to Indianapolis this weekend to hopefully right the ship.
30. Arizona Cardinals (2-2)
The Cardinals' two wins have both come in overtime, and both by the skin of their teeth. If they want to stay in the hunt in a relatively weak NFC West race, the offense will need to be better than a season-high 23 points. Even without David Johnson.
31. Indianapolis Colts (1-3)
The Colts have looked somewhat competitive for brief flashes this season, especially since Jacoby Brissett took over at quarterback. But that might be the ceiling for this team until they put together some semblance of a defense. Even when Andrew Luck returns, it's going to be a tough go for Indy.
32. Cleveland Browns (0-4)
The Browns are one of the youngest teams in the league, and boy are they playing like it. For the first time in years there is optimism in Cleveland, but Hue Jackson's squad has a long way to go on their quest for national relevance.
