THE POWER RANK

NFL Rankings, Week 5

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Okay New England, we get it.  You’re good at football.  And St. Louis, it is likely that you’re already thinking more about the race to acquire Andrew Luck than the race to make the playoffs.  But today I’m not interested in the highs and lows of The Power Rank, I’m taking a shot at it’s sweet, juicy center.

To get a look at what truly constitutes the center of the Power Rank grouping, I used a mathematical formula for Standard Deviation, something that defines the variation from the mean (or average) in a data set.  If you’re enough of a nerd to not stick your tongue out at that definition and want to know more, you can look at Wikipedia’s explanation.

If you’re like me and most math classes made you go crossed-eyed and start drooling on yourself, all you really have to understand is that the bulk of a group (about 68%) falls within 1 standard deviation of the mean on either side, and that the bulk of the remainder (about 27%, for a total of 95% of the whole) falls within 2 standard deviations of the mean.

In other words, teams whose rating falls within 1 standard deviation of the mean (always 0.0 for the Power Rank) are all horribly mediocre.  Ok, that’s my inner pessimist coming out.  A more optimistic view for Eagles and Falcons fans might be to say that they are “on the bubble” when it comes to elite NFL teams (or horrible NFL teams, but we won’t dwell on that).  On the other hand, teams that exceed 2 standard deviations of distance from the mean are truly in a class of their own, either high class or low class depending on which side of the curve they are on.

That’s about as much explaining as I can do, although further questions about the mechanics of this process can be emailed to Ed, who will no doubt be able to give you a thorough explanation of the math that goes into this process.  For my part, I just plug numbers into a free online calculation program and analyze the output.  Ah… sweet, sweet technology.

On to football.

The standard deviation in this week’s power rank is 5.49.  That means that the bulk of teams will fall between 5.49 and -5.49, almost all teams will fall between 10.98 and -10.98, and teams beyond those ratings are truly special.

Congratulations to the Patriots (#1, 15.79) and the Packers (#2, 11.31) for pushing the limits and existing beyond the norm.  Perhaps even more congratulations are deserved by St. Louis (#32, -9.89) for not exceeding the norm…

Very few teams fall between the first and second standard deviations.  On the high side only Baltimore, Detroit, and New Orleans (by a hair) make the grade as especially good teams, whereas on the low end Denver, Arizona, Cleveland, Kansas City, Seattle, and St. Louis all currently qualify as truly not very good teams.

That leaves the other 21 teams in the true statistical middle of the road.  Being in the middle isn’t all that bad, as you are supposedly as close to the top as you are to the bottom.  This is great news for 2010’s weekly bottom dweller Carolina, who finds themselves just within the boundaries of that first standard deviation, but not great news for teams hoping to return strong and make another playoff run like Pittsburgh, Atlanta, or Philadelphia.  Most importantly for these middling teams, their current ratings are not a death warrant for the season, they have no cause for alarm and no need whatsoever to join in the chase for the Andrew Luck Sweepstakes.

A few things to consider for these middle teams:

1.  The current standard deviation is almost 1 point bigger than it was at the end of last year when it ended up at 4.59.

2.  At the end of last season The Power Rank was a little more balanced with one team above 2 standard deviations (New England) and one team below (Carolina).  Currently the two teams exceeding 2 standard deviations from the mean are both on the high side. Most likely, either New England or Green Bay will fall back into the sweet center during the season.

3.  When one (or both) of the juggernauts fall they will bring that standard deviation down with them.  This will cut some teams out of of the running for average status (look out Indianapolis, Jacksonville, and Carolina!) but on the upside a few teams may be thrust into greatness without needing to earn it (it may finally be the year for Houston or San Diego to go all the way).

4.  When the standard deviation shrinks a couple struggling teams may also become hopeless.  But come on, we are only one quarter of the way through the season!  Now is the time for Vikings fans to Ponder over whether or not they can finish out 12-4, Miami fans to Marshall their courage, and Colts fans to…  oh, who am I kidding?  Without Manning they have lost their identity…  they should focus on battling St. Louis and Kansas City in the race for the #1 draft pick in 2012.

NFL Rankings, Week 4

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Upper middle class
The Eagles, Falcons, Steelers
Room for improvement

This week, we see the rankings compress a little bit more, a trend that should continue over the next few weeks as this year’s games stabilize.  The Patriots remain #1 with a 14.73 rating after losing in a shootout with red-hot Buffalo (#13, 1.20).  The Chiefs helped their fans get off the ledge by keeping the game with San Diego (#12, 2.02) to within a field goal, so despite their loss they climb out of the cellar to #30 with a rating of -8.26.  The Rams now occupy the not-so-coveted #32 spot with a rating of -10.96  after a humiliating loss to #3 Baltimore (7.75).

What this means is that last week the range of ratings between #1 New England and then #32 Kansas City was 35.63, whereas this week the difference between #1 New England and new #32 St. Louis is 25.69.  That’s not encouraging news for Rams fans, or for the entire state of Missouri.  What is does indicate is what the scoreboards have shown this year:  no team is utterly dominant (sorry, Mr. Brady) and no team is completely pathetic.  Bad, maybe…  but not insanely horrible as Kansas City’s -19.52 rating last week indicated.

The news is best for fans of the “upper-middle class” of the football teams.  Not the dominant upper crust teams like New England (#1, 14.73, Green Bay (#2, 11.37), and Baltimore (#3, 7.75) with giant stretches of blue glory next to their names.  No, this news is for the fans of teams between rank 4 and 16.  The fans of teams that were supposed to come out with guns blazing, but have somehow tripped over the starting line.  What happened to the free-agent force of the Eagles (#15, 0.82) that was so highly touted by the offseason hype machine?  Wasn’t the return of Matty-Ice with Julio “the missing piece” Jones supposed to take the Falcons (#16, 0.62) from a playoff team to a Super Bowl favorite?  Did the mighty Super Bowl runner-up Steelers really fall to #6 with a good but uninspiring rating of 3.97?

It is these teams who should take note of this week’s movement.  Success in climbing The Power Rank ladder isn’t going to be as much about raising their rating from the 0-4 range up to the heights of Patriots in the teens.  That just won’t happen.  Because the outliers like the Patriots and Packers have little to gain (mathematically speaking) by crushing teams that The Power Rank expects them to crush.  But they can lose a lot by falling to teams who are beneath them.  Even close wins to inferior teams will lower their prestige.  So Big Ben and the Steelers don’t have to worry about trying to hang 70 on the the Brown and the Bengals to catch up.  The Eagles don’t need DeSean Jackson to return 2 punts for touchdowns every game to become elite.  If they can just continue to win for a few more weeks, the over-inflated Patriots and Packers will fall to more reasonable and reachable positions.

*Interesting note:  Running numbers from this year alone, the Bills would be The Power Rank’s chosen team with a rating of 14.28, with the Raiders not far behind with a 13.97 rating.  St. Louis would still be in the cellar, but at an astounding -23.50 instead of their current rating of -10.96.  While the Bills are definitely the hottest team in the NFL and a quickly growing fan-favorite, their official position of #13 suits them quite a bit better.  The Bills have proven that they have the talent, but they still have yet to prove to the league and to the algorithm that they have the ability to be consistent.  Because after all, that is the mark of a true champion.  By considering last year’s data as well as this year’s, The Power Rank cuts through the knee-jerk reactions and keeps the Bills somewhat humble with objective mathematical analysis, while still allowing them room to continue climbing up the ladder if they continue their run of impressive wins.

NFL Rankings, Week 1

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Pittsburgh, still near top
Arizona, not so great
Bills near the middle

Week One in the NFL – a glorious time when half of the league’s team become undefeated and their fans begin talk of this being “the year”, while the other half of the teams wallow in winless shame and their fans open up the forum to the debate over whether to tar and feather or just fire their team’s head coach and general manager.

Here at the Power Rank we pride ourselves in diligently working to stay out of the emotional mire that surrounds the first few weeks of the season.  In the past, we achieved this by quietly sitting back and waiting for a few weeks’ worth of data to roll in before beginning our own talks about who would be in or out of the playoffs.  This year we are boldly stepping up to bring you rankings after only one week of games while still keeping a data-driven analytical view of the game.

This year the early season rankings will account for some past data as well as using this season’s data.  This amalgamation has produced a ranking that places some undefeated teams near the bottom of the pile, while allowing other winless teams to hover near the top.  Let’s take a look at a few key examples:

Pittsburgh – Still Near the Top

The Steelers took one on the chin last Sunday, losing 7-35 to a bitter division rival, the Baltimore Ravens.  In spite of having the second worst season opener (after the Chiefs) in the league, Pittsburgh remains firmly in the top ten Power Rank teams at #8 with a rating of 4.34.  The Power Rank’s algorithm was generous to last year’s Super Bowl runner up because of their stellar showings in 2010 and the fact that the Ravens are a powerhouse as well, starting the 2011 season at #3 in The Power Rank with a whopping rating of 10.15 that is no doubt inflated by coming out and dominating one of the NFL’s more solid franchises.  With most of their talent returning it is a fair assumption to expect the Steelers to come back and earn their high standing in the coming weeks.

Arizona – Stuck in the Cellar

With all of the buzz surrounding the performance of rookie quarterback Cam Newton of the Carolina Panthers, some people seem to have forgotten that he didn’t get the most important stat a quarterback can earn:  a win.  Kevin Kolb arrived in Phoenix this year to help the Cardinals undo the damage the Derek Anderson inflicted on the franchise, if that is possible.  Kolb started the season the right way by guiding the Cardinals to the win column, a place that was largely unfamiliar to them in 2010.  So while Arizona shares the same record as the Patriots (#1), Packers (#2), and Ravens (#3) they are stuck near where they ended last season at #29 with a rating of -9.93.  The Cardinals suffer because The Power Rank is not convinced by a victory over last year’s weekly #32 team, the Panthers, who find themselves in familiar territory in 2011 with a ranking of #32 and a rating of -13.02.  In terms of both Arizona’s record and Newton’s 400+ yard performance The Power Rank is sticking with Public Enemy’s sage advice:  Don’t believe the hype.

Buffalo – Bill-ieve the Hype

Ok, maybe not all of it…  Ryan Fitzpatrick will not likely keep up his 4 touchdown per game pace and end the season with a record shattering 64 touchdowns.  Nor will the Bills be likely to snatch an AFC East title away from the Patriots (#1) or the Jets (#7).  On the other hand, the Bills earned a solid boost in The Power Rank by climbing to #18 with a rating of -0.02 by beating last year’s AFC West champion Kansas City Chiefs, who fell hard to #31 with a rating of -10.66.  Fans of perennially successful franchises may scoff at these numbers, but they indicate that the Bills might just possibly have a team good enough to break .500, or even maybe just possibly sneak into the playoffs.  This is monumental for a team that hasn’t been to the playoffs since the 1999 season, and who have only had one winning season since that year.  Yes, it is too early to say that the Bills are firmly on the rebound, but for Buffalo’s beleaguered fans it is never too early to start partying like it’s 1999.

Week 2 Matchup to Watch – Chicago (#4, 7.90) at New Orleans (#5, 5.22)

Coming off a huge win against 2010 powerhouse Atlanta, Chicago is looking to beat another NFC South juggernaut by stopping Drew Brees and the Saints on their home turf.  With the visiting team holding a slight rating advantage the Power Rank is going to predict that this match is too close to call, and too exciting to miss.

Defense wins championships… or does it?

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For new readers of The Power Rank blog, here’s a brief summary of the week four posting:

“If political strategist James Carville were an NFL pundit he might be telling us ‘It’s the defense, stupid!'”

At that time, the top teams in the Power Rank were defensive powerhouses, with the exception of the then and now offensively dominant New England Patriots.

Now that the NFC and AFC championship games are looming on the horizon, it is again apparent that strong defense is the key to success in the NFL.

The four teams that remain in the Super Bowl hunt are the Steelers, Packers, Bears and Jets.  All of these teams were defensive juggernauts this year.  In the regular season, they ranked 1st, 2nd, 4th, and 6th respectively in points allowed.   What happened to teams in 3rd and 5th place?  Last weekend the 3rd place Ravens lost to the 1st place Steelers, and the 5th place Falcons lost to the 2nd place Packers.

Just take a look at the how the top ten teams in The Power Rank correlate to their rank in points allowed during the regular season:

First, it’s clear that being highly ranked defensively was critical to making the top of The Power Rank this year.  More importantly notice the teams that made the playoffs, and teams still alive in the playoffs…  all of the teams that are still playing have elite defenses, but with the Patriots’ loss on Sunday the best offense left is that of the Packers, the 10th ranked offense in the league.

To see if this was a more universal truth of the NFL, I decided to do some more digging into the success of superior defensive teams in the playoffs.  I started with playoff results by defensive rank since 2002:

Not all seasons have been dominated by defensively superior teams, but overall there is definitely an emerging trend.

While compiling these stats I also noticed that there were a large number of games where teams played opponents of very similar defensive caliber.  It didn’t seem right to me that a 3rd ranked defense beating a 2nd ranked defense be considered the same as a 10th ranked defense beating a 2nd ranked defense.  So I adjusted both wins and losses by separating games where defenses were within three ranks of each other from games where defenses were four or more ranks different:

Now the 55-41 win rate by superior defenses shrinks to 39-28, whereas the record for games between similar defensively powered teams ended up at 16-12.

This result surprised me, since the win percentage for all three of the breakdowns are almost exactly the same:

Apparently the level of difference between the defenses didn’t matter as much as I thought it would.  Regardless of that difference, teams with a superior defense seem to enjoy about a 57% chance of winning in the postseason.  That’s somewhat significant but hardly dominant.

In fact, the only round where the defense seems to make a significant difference is in the divisional round where superior defenses have gone 25-11 over the last nine years, and have had a 69% chance of winning.  The better defense’s chance of winning in any other part of the playoffs?  An even 50%.

It seems clear.  Having the best defense on the field has only mattered for one week a year over the last decade.  The rest of the playoffs seem relatively unaffected by the strength of each team’s defense.

But why does the divisional round seem to favor defenses so much when the rest of the postseason seems utterly unaffected?  To be honest, I’m not sure.  I have some vague ideas, but listing them here would be nothing more than taking shots in the dark.  If you’d like to share your own theories, please feel free to leave a comment.

Homefield Advantage in the NFL

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It’s a nebulous topic.  Whether it’s Our House, The 12th Man, or any other name homefield advantage is an intangible that’s often invoked in football.

This season I attempted to use the Power Rank’s neutral site predictive capability and account for home field advantage…  and failed.  I added an arbitrary three points for the home team, a practice that is relatively common when setting a betting line, but a practice that is hardly scientific.

Rather than develop a complex mathematical matrix to divine the true value of the homefield advantage (I’m just not that smart…  I’ll let Ed work on that!) I decided to poke back into the recent history of the NFL to see is homefield advantage is a truly intangible myth or if it is a real and tangible aspect of the game which might one day be quantifiable.

I gathered data from NFL.com for the years 2002-2010, the only years that represent the current 32 team configuration of the league.

The first thing I wanted to look at was regular season performance.

Since 2002 home teams have won over 57% of the time, while road teams have won only about 43% of the time.  That’s a fairly strong indication that homefield advantage is tangible and meaningful, especially since every year has produced winning records for the home team.  The worst year for home teams since 2002 was 2006, when home teams won barely more than 53% of the time.

There’s a lot that goes into why playing at home is advantageous, from the comfort of your own familiar locker room to the jet lag (or lack thereof) of a coast-to-coast trip to field conditions.  One of the biggest and most obvious advantages is the crowd noise produced by a home team’s fans.  I wondered if this factor would increase the homefield advantage during the playoffs, when fans are going to be louder and more interested in every play of each game.

Here are the results for homefield advantage in the playoffs since 2002, with 2010 incomplete (and not counted):

This time there’s an even stronger correlation between home team and victory in the final win percentage, but the playoffs have special conditions that must be considered before jumping to the conclusion that the correlation is in fact stronger.  First of all, in the regular season the home team is more or less random, whereas in the postseason the home team is determined by the strength of their regular season finish…  usually.

In most cases homefield advantage in the playoffs is awarded to the team with the best record (or by tiebreakers if they had the same record) but this is not always the case.  Division winners are awarded home field advantage over wild card teams regardless of record.  That’s why the 11-5 Saints visited the 7-9 Seahawks, the 10-6 Packers visited the 10-6 Eagles (who they had beat on tiebreakers), the 12-4 Ravens visited the 10-6 Chiefs, and the 11-5 Jets visited the 10-6 Colts last week.

So in the wild card round, you have teams with better records visiting arguably worse teams that won their division.  The results from these four games last week?  A 1-3 record for home teams, with the Seahawks pulling of a somewhat miraculous win over the Saints.

So I also broke down the records of wild card games by homefield:

Not only is this correlation weaker than the homefield advantage in the regular season, its also generally weak.  52.8% versus 47.2% doesn’t create insurmountable odds.  In fact, the odds for an away team to win in the wild card round are about equal to the odds of beating the house on a casino Roulette wheel (with 0 and 00 spaces).

So what happens in the divisional and conference championship rounds when homefield advantage almost always goes to the team with a better record?

Now the correlation is at its strongest, but again the home team is already coming in favored since they usually have a better record, especially in the championship round when the home team always has the better record.

Does this just mean that the better team is winning?  I don’t think so.  The correlations here are significantly larger than the correlation in the regular season, and as all football fans know, the best team doesn’t always show up and win.  I’d attribute the correlation in the later playoff rounds to a combination of the two:  a better team playing at home has a very significantly better chance of winning in the playoffs.

So what does that mean for this week?  All of this week’s match ups feature a weaker team visiting a stronger team.  This is the kind of correlation we see in the conference championship round of the playoffs, about a 69% chance for the home team to win versus 31% for the away team.

Seattle losing to Chicago and New York losing to New England seem like safe bets this week by conventional wisdom, but the other two games are less certain.  Baltimore finished with the same record as Pittsburgh and lost the division on tiebreakers.  The  Power Rank’s #2 team Green Bay visit the Falcons, who needed a few lucky breaks to win at home against the Packers in week 12 this season.

If one of these potential upsets occurs, the record for better teams playing at home this week will be 0.750, close to the expected 0.688 correlation that is shown in the conference championship rounds of the last eight playoffs.

So it seems that homefield advantage is certainly tangible, and is particularly strong when it favors an already superior team (according to record) in the playoffs.