Write On Sports LLC - "A Mathematical Approach to the Divisional Round" by Troy Somero

A Mathematical Approach to the Divisional Round

2007-01-10 12:28:29 | By: Troy Somero

Those who do not learn from history are doomed to repeat it.
--George Santayana

Last week, in an attempt to point out the random guesstimation that is NFL Playoff prediction, I attempted to channel the spirit of historical wit-master Benjamin Franklin. While my Franklin-inspired picks carried me to a 2-2 record last weekend, it is quite clear that 2-2 is not a number that merits satisfaction (unless of course you are Marty Schottenheimer and this really is the NFL Playoffs). Thus, this week I will eschew the historically-inspired prognostication and utilize some basic algebra to determine who will win this weekend's NFL Divisional Round games.

I have taken the following approach to my mathematical predictions for this weekend: some statistics are much more important than others. For example, it is great that San Diego is first in the NFL with 30.2 points-per-game on the season, but that statistic does not tell me how many points San Diego allowed per game this season (18.9). Therefore, it is not only important to list statistics but also to compare offensive and defensive statistics to determine which teams truly are dominant (Baltimore) and which teams appear to be more dominate than they really are (San Diego).

I have chosen five statistics in particular to determine which four teams I believe will advance to their conference championships on January 21. Every time a team wins a statistical match-up over its opponent - by having a higher positive statistical value than the opponent - it will earn a point. The team with the most points after the five match-ups is the team that I predict will win this weekend.

Note: I did not look at any of these statistics before I proposed this formula. Even though I criticize Marty Schottenheimer over and over in this article, I, at this point in time, have no clue how favorably San Diego will match up against New England.

1. Point Differential (per game) – Like I stated above, it is helpful to know how many points a team scored, but that statistic does not provide anyone with enough information in of itself to "bet the farm" on any team in particular this weekend. A team's point differential (per game) is much more effective in demonstrating just how dominant a playoff team has been this season.

2. Turnover Differential (average turnover margin/game) – This statistic can be viewed in the same light as the statistic described above: some teams turn the ball over often, while other teams turn the ball over less often. Some teams cause many turnovers, and other cause fewer turnovers. Stating that Team X caused 40 turnovers this season does little to tell a football fan what affect this number had on the teams overall ability to hold on to the ball. Turnover differential (displayed below as average turnover margin per game) tells the complete turnover story in an easy-to-read number with a decimal point.

3. Difference of Redzone Touchdown Percentage (Scored) to Redzone Touchdown Percentage (Allowed) – This statistic is a little more complex but I believe it is an important number that I wish I had seen before I actually calculated it myself. Teams that enter the redzone and score touchdowns with great frequency have an obvious advantage over teams that score less frequently. By the same token, defenses that give up redzone touchdowns with less frequency have an advantage over defenses that surrender a higher number of touchdowns per redzone opportunities. This statistic encompasses both offensive and defensive numbers and is thus very informative in describing how effective a team is in the redzone on both sides of the ball.

4. Difference of 3rd Down Conversion Rate (Offensive) to 3rd Down Conversion Rate (Defensive) – Anyone who watched the Seattle/Dallas game last weekend knows how pivotal third-down conversions are. Had Dallas converted that late game third down near the Seattle goal line, Tony Romo would never have had to attempt his ill-fated hold on the next play. Like the statistic above, this number takes offensive and defensive numerology together in order to determine how successful a team is on third down, whether that team is snapping the ball or attacking the snapper. It may be cliché to say, but it is a fact that teams that are successful on third down win football games with a greater frequency than teams that are not successful in similar circumstances.

5. Head Coach's Postseason Winning Percentage – While this statistic does not relate to a specific group of events on the field, it encompasses the overall success of a team's strategy. Coaches that make wise decisions and develop successful game plans allow their teams to have a much better shot at winning than coaches who panic under the pressure and devise ill-suited game plans. One of the major reasons that New England has won three Super Bowls is because of the game plan in each game of Bill Belichick and Company. For anyone who does not believe coaches play a significant role in a team's postseason success, I have two words for you: Marty Ball.

The first game of the weekend – Indianapolis at Baltimore – should be a runaway for Baltimore. The Ravens are more efficient in virtually every aspect of the game broken down below and their coach (Brian Billick) has a Super Bowl ring.

Indianapolis
1.) Pt. Diff./Game: 4.2
2.) TO Diff./Game: .438
3.) Redzone TD Ratio Diff.: .013
4.) 3D Conv. Rate Diff.: 9.0
5.) HC PS Win %: .385
POINTS: 0

Baltimore
1.) Pt. Diff./Game: 9.5
2.) TO Diff./Game: .938
3.) Redzone TD Ratio Diff.: .090
4.) 3D Conv. Rate Diff.: 12.4
5.) HC PS Win %: .571
POINTS: 5

Likewise, Chicago should have a relatively easy time eliminating Seattle. In fact, the Seahawks are statistically the worst team by far in the playoffs (thanks to their weak division ushering them into the playoffs). The Seahawks gave up more points than they scored, turned the ball over more often than they forced turnovers, and gave up more redzone touchdowns than they scored. Even though Lovie Smith is only 0-1 in the playoffs and Mike Holmgren has won a Super Bowl, no coach can overcome a squad this inferior to win on the road in Chicago on Divisional Weekend.

Chicago
1.) Pt. Diff./Game: 10.8
2.) TO Diff./Game: .813
3.) Redzone TD Ratio Diff.: .005
4.) 3D Conv. Rate Diff.: 5.8
5.) HC PS Win %: .000
POINTS: 4

Seattle
1.) Pt. Diff./Game: -.4
2.) TO Diff./Game: -.560
3.) Redzone TD Ratio Diff.: -.044
4.) 3D Conv. Rate Diff.: 1.4
5.) HC PS Win %: .550
POINTS: 1

The statistical surprise is a Philadelphia victory over New Orleans. Even though he is the NFL Coach of the Year, Sean Payton is in his first season as a head coach and therefore has no playoff winning percentage. Andy Reid, on the other hand, has the best winning percentage of any coach left in the playoffs not named Bill Belichick. The Saints are more solid with respect to scoring and third-down conversations, but the Eagles counter this with a better turnover margin and better redzone execution this season. * Philadelphia* will win on the road, but it will be a close game and I would recommend putting your money on the "under" if you are betting against the point spread.

Philadelphia
1.) Pt. Diff./Game: 4.4
2.) TO Diff./Game: .313
3.) Redzone TD Ratio Diff.: .077
4.) 3D Conv. Rate Diff.: 4.7
5.) HC PS Win %: .583
POINTS: 3

New Orleans
1.) Pt. Diff./Game: 5.7
2.) TO Diff./Game: .125
3.) Redzone TD Ratio Diff.: .010
4.) 3D Conv. Rate Diff.: 10.2
5.) HC PS Win %: .000
POINTS: 2

The New England/San Diego game is the last game of the weekend with good reason: it will probably be the most exciting game. The 2006 NFL season's best player and best team versus the pre-eminent franchise of the decade. The Chargers take the lead in points and turnovers but are much less effective in the redzone than the Patriots. Both teams are identical in third-down conversation rate (which I believe is a telling sign of how good this match-up really will be), which means the Chargers would win 2-1 if coaches were taken out of the equation. However, coaching is never out of the equation in the playoffs. The Belichick/Schottenheimer showdown evens the score to a 2-2 draw, but ultimately it will be New England that pulls off the road upset thanks to the advantage on the sideline.

New England
1.) Pt. Diff./Game: 9.3
2.) TO Diff./Game: .313
3.) Redzone TD Ratio Diff.: .257
4.) 3D Conv. Rate Diff.: 6.6
5.) HC PS Win %: .846
POINTS: 2

San Diego
1.) Pt. Diff./Game: 11.9
2.) TO Diff./Game: .813
3.) Redzone TD Ratio Diff.: .103
4.) 3D Conv. Rate Diff.: 6.6
5.) HC PS Win %: .294
POINTS: 2

Addendum: I have emphasized throughout the year that a team's schedule has a major effect on that team's regular season and postseason successes. I have also drawn much criticism about this from some of my readers (mostly Bears fans because I have been so unimpressed with their team this season). For the sake of this week's article I have taken this personal bias out of my argument, even though many of these statistics are based on a team's strength of schedule.

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