Last year, I derived implied SRS Ratings for each NFL team based on the initial Vegas point spreads. Well, lines have been set for the first 240 games of the year — i.e., every week but week 17 — which means we can re-run the exercise for 2014.
So how do we use point spread data to derive SRS ratings? The point spread in each game provides an implied strength margin (“ISM”) between the two teams: When the Raiders are 10-point home underdogs to Denver, that implies that Denver is 13 points better than Oakland. If we treat each ISM like we would margin of victory, then we can use the SRS to come up with team ratings. For those who need a primer on what the SRS is, you can read about it here; the rest of you can skip to the ratings:
This time last year, the top five teams were…. well, the exact same five teams, albeit in a slightly different order. And the bottom three teams were… Jacksonville, Oakland, and Tennessee, in that exact order. The Broncos have the largest average margin of victory [1]Just to be clear, this analysis includes 3 points for each home team except in the London games, so these are more accurately thought of as location-adjusted expected margins of victory., but because the Seahawks face a tougher schedule, the Seahawks are implied by Vegas to be the strongest team in the NFL at six points better than average.
One interesting way to use the SRS is to see which teams have the hardest schedules. Pre-season strength of schedule is essentially meaningless when based on last year’s record, but the SOS ratings here are based on the implied strengths of each team. In my opinion, you’d be hard-pressed to find a better set of strength of schedule ratings in May than what we see here (other than the fact that they exclude week 17).
The toughest schedule this year belongs to Arizona: add in the oldest roster in the league in 2013, and it’s easy to see why Vegas is so bearish on the Cardinals in 2014. The Seahawks (+0.92) and 49ers (+0.81) have two of the next three toughest schedules (with the Panthers sandwiched between them). The Rams are a few spots down, but remember: this is only the strength of schedule for the first sixteen weeks of the season. St. Louis travels to Seattle in week 17, so the Rams schedule would be just as brutal if we included that game. The Bears having one of the five hardest schedules is a surprise after having such an easy slate in 2013. It’s true that this analysis ignores that Chicago gets to play Minnesota in week 17, which would ease their schedule strength, but the Bears face the 49ers, Patriots, Saints, and Panthers this year, along with two games against Green Bay. That’s six games against top-7 teams.
Three AFC South teams have the easiest schedules; the Jaguars would probably join the rest of the division if they had two games against Jacksonville. The Texans are set up nicely for a rebound season under Jadeveon Clowney, Bill O’Brien, and, uh, Ryan Fitzpatrick/Case Keenum/Tom Savage. What’s really incredible about Houston’s schedule: not only do the Texans have the easiest schedule through 16 weeks, the Texans host the Jaguars in week 17! Including that game would bring Houston’s schedule down to 1.9 points easier than average.
If you include that game, 8 of the Texans’ 16 games are against teams that are 1.5 points weaker than average. Playing six games against the AFC South, the NFC East and the AFC North, and the Bills and Raiders makes for about as easy a schedule as one could create. Assuming the Texans would be favored in week 17, that means Houston — which went 2-14 last year — is favored in 8 of 16 games and a pick’em in three others (Philadelphia and Cincinnati at home, Tennessee on the road). That’s pretty incredible, and explains why Vegas was so bullish on Houston.
The table below shows each game in the first sixteen weeks of the 2014 season. Here’s how to read the Seahawks/Raiders line: In week 9, Seattle hosts Oakland. The line is -14.5, which means the Seahawks are 14.5-point favorites. Seattle’s SRS is 6.0 while Oakland has an SRS of -5.8. Therefore, the line predicted by the SRS would be Seattle -14.8 (since the Raiders are 11.8 points worse than the Seahawks and on the road). The difference between the actual line and the SRS line is -0.3 points. By definition, the sum of all the differences between the actual lines and SRS lines must be 0, since the SRS lines were generated from the actual lines. The table below contains 480 rows, showing each game from the perspective of both teams (although the only searchable column is the first team column):
Some thoughts:
- The biggest outlier games are again in week 1; as Jason Lisk noted when he ran a similar study last year, the lines build in some risk of injury (or simply risk of not knowing what’s going to happen in the future): if Aaron Rodgers or Peyton Manning miss time with an injury, it’s more likely to be later in the season than in week one. Additionally, if Vegas feels more confident in the early games than the late games, that will lead to some games appearing as outliers in week 1.
- The weirdest line of the season is Tennessee/Kansas City in week 1. The Chiefs are only 5-point home favorites: that’s 2.1 points lower than we would expect given the location of the game and the ratings of Kansas City (+0.8) and Tennessee (-3.3).
- As a reminder, here’s a link to the 2014 schedule grid I created; I did not assign 3 points to the home team in the three London games this year.
- For the second straight year, the Seahawks are underdogs just once: the game in San Francisco. Denver is an underdog when it travels to Seattle and Foxboro, and every other team is a dog in at least three games.
- Oakland and Jacksonville are underdogs in each of their 15 games. Considering Oakland travels to Denver in week 17, we can safely say the Raiders and Jags are projected underdogs in every game this year.
References
↑1 | Just to be clear, this analysis includes 3 points for each home team except in the London games, so these are more accurately thought of as location-adjusted expected margins of victory. |
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