## Wednesday, January 5, 2011

### Total team luck points and no luck power through week 17

by Bruce D

Team luck points = (bad luck points)-(good luck points), so negative numbers are the luckiest
For a more in-depth explanation of what "luck" points are, go to a previous post here.
Luck is tracked to better analyze a team's true ability and to help predict results of upcoming games where some may not know what portion of a team's record and points performance was due to just luck.

Luck points are valued as follows:

Points for(+) the unlucky team, are the same amount of points against(-) the lucky team.

punts blocked=3
interceptions=2.5
fumbles lost=2.5
field goal miss/block=2.5
punt returns for a TD=4.5
ko returns for a TD=4.5

 Season Team All Season Last 3 Games Last 2 Games Last Game 2010 nwe -87 -32 -27 -9.5 2010 atl -49 -12 -7 -7 2010 pit -38 -0.5 -5 -7.5 2010 bal -27 -20 -17.5 -10 2010 tam -25 0 0 -2.5 2010 phi -24.5 10.5 12.5 5 2010 nyj -22 -17 -12.5 -12.5 2010 chi -21.5 -14.5 0 0 2010 gnb -18 -7.5 -12.5 0 2010 kan -14.5 2.5 5 2.5 2010 ari -11.5 2.5 0 5 2010 oak -10 -4.5 -9.5 -2.5 2010 ten -7.5 0 0 2.5 2010 hou -5.5 -7.5 -7.5 -7.5 2010 cle -2.5 15 15 7.5 2010 ind -1 -0.5 4.5 -2.5 2010 sfo -0.5 -2 -4.5 -5 2010 stl 1 2 -0.5 0 2010 det 4.5 -5 -5 2.5 2010 dal 6.5 -5 0 -5 2010 den 10 -9.5 -4.5 -4.5 2010 sea 10.5 2.5 -2.5 0 2010 nyg 14.5 7 5 -7.5 2010 nor 15 5 2.5 2.5 2010 was 15.5 7.5 2.5 7.5 2010 buf 20.5 17.5 30 12.5 2010 min 22 4.5 -10 -2.5 2010 car 26.5 2 4.5 7 2010 cin 34.5 7.5 7.5 10 2010 jac 44.5 17.5 12.5 7.5 2010 sdg 55 4.5 7 4.5 2010 mia 64.5 29.5 17 9.5

Power is derived by calculating each team's offensive and defensive points production and prevention for each game, comparing it to the league average each week, and then adjusting for strength of opponent.

Next, all lucky type plays, good or bad, such as interceptions, fumbles lost, blocked punts, kick off return touchdowns, missed field goals etc. are valued, and each team's power is adjusted by a portion of this luck value. If a team has been overly lucky, their power will be adjusted lower due to the fact that they can't be expected to continue to be so lucky. For the same reasons, an unlucky team's power will be increased.

A power rating of 1 is considered league average, so a team with a rating of 1.2 can be thought to be 20% better than the average team, and a team with a rating of .85 can be thought to be 15% worse than average.

 Rank Team Power 1 gnb 1.169 2 pit 1.156 3 sdg 1.156 4 nwe 1.132 5 bal 1.087 6 atl 1.083 7 nor 1.075 8 nyg 1.06 9 ind 1.055 10 nyj 1.055 11 phi 1.044 12 oak 1.042 13 chi 1.039 14 mia 1.025 15 det 1.017 16 kan 1.006 17 dal 1.005 18 ten 1.004 19 tam 1.002 20 jac 0.995 21 cin 0.99 22 min 0.986 23 sfo 0.985 24 hou 0.983 25 cle 0.967 26 was 0.964 27 stl 0.953 28 den 0.944 29 buf 0.933 30 sea 0.925 31 ari 0.865 32 car 0.859

It's surprising to me how similar the first list is to must conventional power rankings. Obviously there's going to be a few outliers in the middle (and SD of course is at the very bottom), but seeing Patriots, Falcons, and Steelers at the top is priceless. You gotta be lucky to win.

Eric Moore said...

I like what you're trying to do here, but I'm not sure about how you've defined luck. I would say that a team which loses only 4 out of 16 fumbles, for example, is extremely lucky, while a team that loses 4 out of 6 fumbles may actually be unlucky if we assume that not fumbling is a repeatable skill.

To some extent, this may explain what Adam H noted about how the luck rankings resemble traditional power rankings. Perhaps good teams minimize the chances to get unlucky on offense and maximize the chances to get lucky on D.

Bruce D. said...

Eric,

What I try to do is track what actually affected the game in a lucky or unlucky way.

What you said
"I would say that a team which loses only 4 out of 16 fumbles, for example, is extremely lucky, while a team that loses 4 out of 6 fumbles may actually be unlucky if we assume that not fumbling is a repeatable skill."
seems true and reasonable, but not my goal.

I'm trying to track which points are real, and which points are due to luck, not so much who's the luckiest team. That's just a byproduct.