On Payroll and Depth during the Holiday Fixtures

Published at ESPN.

How Payroll Predicts Holiday Outcomes in the EPL:

Clubs with wage bills among the top four in the league tend to do very well no matter the circumstance, but particularly at the New Year. They average about 2.0 points per match over most of the season; during the holidays, that rate jumps 10 percent to 2.2 points per match. This means that every festive period, one of the four richest clubs wins a match they otherwise would have drawn or lost. Given that the title and fourth place races are often decided by a point or two, those extra points at the holiday can make all the difference.

At the same time, not every high-payroll club sees the benefits of depth every year. If a high-payroll club like Manchester United or Arsenal goes on a run through the winter fixtures, it should not be surprising, but such a run is in no way guaranteed.

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World Cup Projections

(Note: these didn’t turn out so great.)

Published at SB Nation.

2014 World Cup Projections:

The hardest part of building an international football ranking system is dealing with strength of schedule. By raw goals ratio, the three best teams in the world over the last several years are Brazil, Spain and Germany. That sounds good, but fourth is… Iran. Without accounting for schedule, there is no way to do this sort of analysis.

Team Trends in Chance Quality

Published at SB Nation.

Shot Matrix IV: Team Trends in Chance Quality:

Now, one of the peculiarities of shot quality is that there are lots of ways, tactically, to take good shots. Arsenal are the classic example, they pass and pass, looking especially for through-balls into dangerous areas, and eventually look to “pass it into the net.” The traditional passing game is our primary model of high-quality shot-taking, but in fact it’s not the only one.

The exact opposite tactical method, the “go 4-4-2 and put crosses in” strategy, also produces high-quality shots. If your primary strategy around the box is to get the ball wide and try to play crosses into dangerous areas, you’re going to be taking relatively few low-value speculative long balls. And even though shots off crosses from close areas have lower expectation than normal shots from these areas, they’re still a lot better than shooting from outside the box or from wide areas in the 18-yard box. A bunch of those dots in the top right are Arsene Wenger’s clubs, but another good portion are Tony Pulis.

Shot Type and Location Studies

My first expected goals studies, published at SB Nation.

Shot Matrix I: Shot Location:

Shots from outside the box kind of suck. If you really do have a shooting lane to put the ball on target, they’re not necessarily the worst, but a huge percentage of shots from outside the box result in turnovers, either goal kicks or blocked shots that can produce transition opportunities. The cost of shots from outside the box comes in those 75% of instances when the keeper is not called into action at all.

Shot Matrix II: Headers and Crosses:

Once you get outside of the six-yard box, chances off crosses and headers lose a lot of their value. I like how the numbers on headers off crosses and other headers converge to an 8% conversion rate by quite different means. Hitting a cross ball with your head from twenty feet or more and putting on target is very difficult. If you do get it on target, there’s at least a non-terrible chance that you got enough power and precision behind the ball to score. On other headers, where the ball is most likely coming in at a kinder speed and angle, directing it to goal is relatively easy. Beating the keeper, though, is incredibly difficult as you rarely get enough power on the header to trouble the keeper.

Shot Matrix III: The Incredible Through-Ball:

I have a total of 1738 shots off through-balls logged in my database. A negligible number come from either outside the box or from Zone 1. No professional keeper would stand rooted to his line as a pass split his defense which allowed an attacker to run onto the ball in the center of the six-yard box. I presume that the 12 shots off through-balls from Zone 1 in my database represent shots where the attacking player collected the ball further from goal, rounded the keeper, and then finding himself in front of goal, took the shot.

Comparisons Between European Leagues

Published at SB Nation.

Shot Matrix International I: The Differences Between the European Leagues

The primary driver of England’s shot total, compared to the other largest continental leagues, is shots taken from the danger zone. That’s the old English directness right there.

If we look at shots from a wide angle inside the box, we see a very different picture. Despite the larger number of shots taken overall in the EPL, there’s no meaningful difference in total shots taken from wide areas inside the box. And when we narrow down just to shots from a difficult angle inside the box, the numbers really jump out. There are far more shots taken from those difficult angles in Spain and Italy than in England and Germany.

Shot Matrix International II: Shot and Pass Type

The zone-by-zone breakdown doesn’t teach us much. But the broader point here is that shots assisted by through-balls are attempted at massively differing rates. These tend to be extremely high-quality shots, converted at rates double or more regular shots from the same area. A successful through-ball by definition splits the defense and leaves an attacking player in space. We should expect higher rates of shot conversion in leagues where these sorts of attempts are more prevalent.

Player Shooting Skill Studies

Published at SB Nation.

Shot Matrix V: Identifying Player Finishing Skill

I could only identify an effect with samples of minimum 100 shots, and even then the effect is not overwhelming. (See Nerdery section below for more.) If a player has taken 20 or 30 shots but converted either a lot more or a lot fewer than you’d expect, you’re still best referring to the studies showing no y-to-y correlation in shot conversion. Probably it’s been a fluke. There’s a possibility that it isn’t, but the only good way to identify that statistically is with several seasons of data. So we need to be very careful about concluding that a player really has a significant shooting skill.

Player Finishing Skill is Real

When you aggregate data and collect groups of similar players, there emerges a clear tendency of higher-volume shooters and more advanced players to finish their chances more efficiently. I think this is a selection effect. Football managers recognize which of their players have the best striking skills and arrange tactics to get those players the most chances.

The Value of the Through-Ball

Published at SB Nation.

Shot Matrix III: The Incredible Through-Ball:

The average shot taken in the English Premier League from 2009-2013 has an expected goals value on 8.7%. Arsenal’s shots have an expected goals value of 10.1%. Over a sample of 2693 shots, that is a difference highly unlikely to occur by chance. To put a number of it, there is less than a 1% chance of a club averaging a shot quality that far above league average, on that many shots, by pure random variation. It’s a real tactical effect.