Quantifying Kicker Ability: Introducing Points Over Expectation

This is the first in what I hope to be the beginning of data-driven projects here on manwithaspreadsheet.com. In the data rich world of sports, it is incredibly difficult to quantify an individual’s performance independent of those around him in America’s most popular sport, football. This study has one primary goal: to quantify the value of kickers by comparing their points against the expected points of their peers.

What is expected points? Expected points is the likelihood of conversion times 3 (points for a field goal). About 2/3 of 50-yard field goals were converted over the time frame of this study (2008 to 2014 seasons). If a kicker were to convert a 50-yard field goal, they would have achieved 3*(1-2/3) POE, where as a failure would result in 3*(0-2/3) POE. Unlike measurements such as WAR, which compare to replacement level, a POE of 0 indicates a league-average kicker. POE is a better measurement than field goal percentage, because it takes into account the distance of the attempted kick. Adam Vinatieri was 30/31 in 2014, but his POE was a point less than Steven Gostkowski who was 35/37 in 2014, because he attempted more difficult field goals. A kicker should not be punished for missing a 60-yard field goal as much as a 25-yarder.

All of the data below was gathered using play-by-play data on nflsavant.com. Blocks were considered the same as a miss for the purposes of this study. Since there are some limitations of data sample size (for instance 25-yard field goals were converted 5% higher than 24-yard field goals) I applied exponential regression to the equation.

Best kickers over course of study:

Player POE Kicks POE/Kick
D.BAILEY 29.9 127 0.235428
J.TUCKER 25.6 108 0.236668
S.JANIKOWSKI 23.6 225 0.104904
R.BIRONAS 21.9 185 0.11847
A.VINATIERI 19.9 200 0.099332

Worst kickers:

Player POE Kicks POE/Kick
N.FOLK -18.8 219 -0.08573
G.GANO -20.2 155 -0.13025
D.AKERS -26.3 253 -0.10407
M.CROSBY -29.1 241 -0.1206
B.CUNDIFF -29.2 169 -0.17298

Greatest value added per kick (min 30 kicks):

Player POE Kicks POE/Kick
J.TUCKER 25.6 108 0.236668
D.BAILEY 29.9 127 0.235428
J.BROWN 17.4 100 0.174388
C.CATANZARO 4.7 33 0.14335
R.BIRONAS 21.9 185 0.11847

Worst season: David Akers -18.2 POE in 2012.

Best season: Blair Walsh 13.3 POE in 2012.

There are no park-adjusted factors for domes or cold-weather stadiums. Also the calculated expectancy uses a sample from 2008 to 2014 even though kicking ability has steadily increased over those 7 seasons. This metric also fails to quantify the kicker’s ability on kickoffs, but perhaps that could come in a future study. Justin Tucker and Dan Bailey have emerged as the stars from this study, accounting for an average of 7-plus points per season since being drafted in the early 2010’s and being worth about 0.4 points per kick more than Billy Cundiff.

Questions/Comments @manwithaspreads

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