Thursday, February 19, 2015

Wednesday, February 18, 2015

Route One Football Rankings (MLS + EPL)

Higher % = more direct.  Definitely some stylistic differences between MLS/EPL.


Wednesday, January 14, 2015

Goalkeeper Stats Are (Mostly) Stupid


DC United's Bill Hamid had a great year in 2014, helping to lead a resurgent season for Ben Olsen's club.  Hamid led MLS in Save % and deservedly won the MLS Goalkeeper of the Year Award.  The other goalies receiving consideration also were near the top of the league in Save % (poor Jon Busch).

Tracing back through the recent history of the award this same trend can be seen: the "best" goalies have the highest Save %.  This seems reasonable; most of a goalie's worth to his team is measured by how good they are at stopping shots on target from reaching the back of the net (measured as Save %).  Therefore, it is intuitive that the "better" the goalie the higher their Save %.  If this is the case we would expect the best goalies to consistently outperform their counterparts year over year.  So we tested the persistence of Save % based on a sample of MLS goalies (2011-2014 seasons) who played a minimum of 2,000 minutes.  It turns out Save % is a horrible predictor, with absolutely zero relationship between Year 1 Save % and Year 2 Save %.  Breaking the stat into its components (Inside the Box Shots, Outside the Box Shots) did not help, either.

What does this mean?  For one, it confirms what most of the analytic community has known for some time: evaluating goalies statistically is really difficult.  It also, at least to me, confirms that luck/variance trumps skill when we evaluate goals scored (for strikers) or goals allowed (for goalies).


Wednesday, December 31, 2014

Measuring Referee Bias in BPL



Ask any fan their opinion of BPL referees and the responses will range from "mediocre" on the positive side of the spectrum to "#$%&..." on the more negative side.  These fans make their feelings known every match day, often vociferously.  It is possible that certain referees may hold biases against certain clubs, players or managers, but- in particular- the home/away bias has been noted in a multitude of prior studies.

Perhaps the most subjective decisions, and therefore most susceptible to bias, a referee makes is determining when a card should be shown to an offending player.  These decisions can often appear maddeningly inconsistent.  Indeed, we looked at the number of fouls committed per card for each BPL team (home and away) and found a pretty significant difference.  On average it takes a home team 6.6 fouls before they receive a card while for away sides it only takes 5.6 fouls.  Perhaps, just as a player might be said to "see red" in a fit of madness, a "yellow mist" might besiege a referee in front of thousands of baying fans.

See below for a team by team breakdown.  Chelsea is subject to the largest disparity in home/away fouls per card.


Tuesday, November 11, 2014

On Southampton's Stingy Defense

This article originally appeared in BSports



Southampton are enjoying a tremendous start to the season.  They are currently in second place on the table after 11 played, four points clear of Manchester City and have allowed only five goals, less than half a goal a game.  The Saints have been great defensively, though their astonishing goals allowed rate may be due to regress.  A major factor in the team’s defensive success has been their ability to limit opposition possession in their defensive 3rd.

Final 3rd Passes Allowed PG
Arsenal
101.2
Southampton
107.8
Manchester City
113.2
Manchester United
113.7
Newcastle United
121.3
Everton
122.2
Chelsea
124.5
West Ham
124.6
Stoke City
124.8
Tottenham Hotspur
126.5
West Bromwich Albion
126.6
Liverpool
130.4
Burnley
141.4
Queens Park Rangers
143.5
Swansea City
150.7
Leicester City
153.0
Hull City
157.0
Sunderland
159.1
Aston Villa
165.5
Crystal Palace
167.1

But the team’s defensive success starts further up the pitch.  Southampton leads the BPL in number of possessions won in the middle 3rd of the pitch, and the team has three of the top 10 individuals in the metric.  In particular, midfielders Victor Wanyama and Morgan Schneiderlin have done a great job of snuffing out opposition possession before it becomes dangerous.  Even striker Shane Long is getting into the act.

# Poss Won  Middle 3rd / 90
Victor Wanyama
Southampton
7.4
Charlie Adam
Stoke City
6.3
Fernandinho
Manchester City
6.0
Scott Arfield
Burnley
5.2
Tom Huddlestone
Hull City
5.0
Nemanja Matic
Chelsea
5.0
Alexandre Song
West Ham
5.0
Carlos Sánchez
Aston Villa
5.0
Shane Long
Southampton
4.8
Morgan Schneiderlin
Southampton
4.7