When Hernandez scored for Manchester United in the first minute of play against Chelsea today on a fast break after a beautiful pass from Park, it reminded me of the high value such shots have for teams. Mind you, these kinds of opportunities don't come along all that much in the average match: I have previously noted that teams actually create relatively few shots from fast breaks. Data from the Opta/Guardian chalkboards show that Premier League teams, on average, took about 15 shots per match in the first half of this season (14.7 to be exact). But by far most common shots were generated from open play (11). In contrast, shots from fast breaks are pretty rare; on average, teams created only half a shot per match from fast breaks (.52), while they generated about four times as many shots from corners (2.1) and about 50% more from free kicks (.82). The only shots more uncommon than shots from fast breaks are penalty kicks.
While shots from fast breaks may be rare, they also are much more likely to pose a threat to the other side. When we break down the data and look only at those shots that were accurate and thus had a real chance of yielding a goal, we see that the odds of shots created from open play being on target are right around the average in accuracy (around .3) and shots created from corner situations least likely to be on target (at .2). In stark contrast, shots created from transition play (fast breaks) were the most likely to be accurate (ignoring penalty kicks for a moment), at a rate of .43. Clearly, shots from transition play are particularly valuable for teams because they have a much higher chance of being accurate than the average shot.
These averages help us to benchmark team performance, but of course they also typically disguise differences across teams. When we looked at overall shot creation from fast breaks, the data showed that there was quite a mix across teams with regard to who was able to create shots from transition play. The top five performers in the first half of the season included the top three teams (Arsenal, Chelsea, and Man U), but also teams further down in the table (Sunderland and Birmingham) at over .8 shots from fast breaks per match.
At the other end, Wolves, Fulham, and Newcastle created about a fourth of that (.2 shots) per match. One surprise was how similar the profiles of Wigan and Man U were on this dimension, and how mixed the teams were generally.
So something happens between creating a shot and actually scoring for each of these teams to generate the match outcomes we all know (and that's not mentioning defense). So the next question is whether the teams that created more shots from fast breaks also created more accurate shots. Here are the numbers for comparison.
Surprised? I was. Turns out, when it came to creating accurate shots from fast breaks, Wigan were the winner of the first half of the season at over .4 accurate shots per match. This is perhaps the most interesting finding so far, as Wigan outdid the likes of Man U, Man City, and Chelsea on this dimension.
Clearly, there's slippage between creating shots and creating accurate shots. So another way to look at team performance and to measure this slippage is to see how efficient teams were in generating accurate shots. To understand with a little more precision how teams performed, it helps to look at proportions or ratios. So here are the ratios of accurate shots relative to all shots created from fast breaks.
Recall that the overall average ratio of accurate to all shots is .3 and that shots created from transition play (fast breaks) were the most likely to be accurate (except for penalty kicks of course), at a rate of .43.
How did teams stack up halfway through the season? Arsenal on one end and Fulham and Wolves on the other were curiously and unexpectedly distinct on generating accurate shots from fast breaks. While Arsenal led the league in generating the greatest number of shots from transition play, they were woefully inefficient, finding themselves at the bottom of the efficiency scale. In contrast, Fulham and Wolves produced few chances from fast breaks; but when they did, they were highly accurate in the shots they generated.
While shots from fast breaks may be rare, they also are much more likely to pose a threat to the other side. When we break down the data and look only at those shots that were accurate and thus had a real chance of yielding a goal, we see that the odds of shots created from open play being on target are right around the average in accuracy (around .3) and shots created from corner situations least likely to be on target (at .2). In stark contrast, shots created from transition play (fast breaks) were the most likely to be accurate (ignoring penalty kicks for a moment), at a rate of .43. Clearly, shots from transition play are particularly valuable for teams because they have a much higher chance of being accurate than the average shot.
These averages help us to benchmark team performance, but of course they also typically disguise differences across teams. When we looked at overall shot creation from fast breaks, the data showed that there was quite a mix across teams with regard to who was able to create shots from transition play. The top five performers in the first half of the season included the top three teams (Arsenal, Chelsea, and Man U), but also teams further down in the table (Sunderland and Birmingham) at over .8 shots from fast breaks per match.
At the other end, Wolves, Fulham, and Newcastle created about a fourth of that (.2 shots) per match. One surprise was how similar the profiles of Wigan and Man U were on this dimension, and how mixed the teams were generally.
So something happens between creating a shot and actually scoring for each of these teams to generate the match outcomes we all know (and that's not mentioning defense). So the next question is whether the teams that created more shots from fast breaks also created more accurate shots. Here are the numbers for comparison.
Surprised? I was. Turns out, when it came to creating accurate shots from fast breaks, Wigan were the winner of the first half of the season at over .4 accurate shots per match. This is perhaps the most interesting finding so far, as Wigan outdid the likes of Man U, Man City, and Chelsea on this dimension.
Clearly, there's slippage between creating shots and creating accurate shots. So another way to look at team performance and to measure this slippage is to see how efficient teams were in generating accurate shots. To understand with a little more precision how teams performed, it helps to look at proportions or ratios. So here are the ratios of accurate shots relative to all shots created from fast breaks.
Recall that the overall average ratio of accurate to all shots is .3 and that shots created from transition play (fast breaks) were the most likely to be accurate (except for penalty kicks of course), at a rate of .43.
How did teams stack up halfway through the season? Arsenal on one end and Fulham and Wolves on the other were curiously and unexpectedly distinct on generating accurate shots from fast breaks. While Arsenal led the league in generating the greatest number of shots from transition play, they were woefully inefficient, finding themselves at the bottom of the efficiency scale. In contrast, Fulham and Wolves produced few chances from fast breaks; but when they did, they were highly accurate in the shots they generated.
To see how profligate Arsenal were, consider these numbers. While they, on average, created .82 shots from transition play, they managed .24 accurate shots from fast breaks per match. In contrast, Wolves managed only a fifth of what Arsenal were able to do in terms of generating shots (at a rate of .18 per match), but they also managed to produce .12 accurate ones. So viewed from a pure efficiency perspective, Arsenal were much more inefficient than Wolves.
Now, would you rather be Arsenal and inefficient or Wolves and efficient? I'll leave that to you, but that's kind of beside the point. The numbers tell us something about the teams' offensive capabilities. Wolves' (and Fulham's, for that matter) relatively high efficiency rates tell us that their weakness is not in making the shots they created from fast breaks accurate; it's in creating them in the first place. Arsenal's weakness is the reverse: while they create plenty of chances from transition play, they could work on making more of them count.
Here's why it matters. The next graph shows the average number of shots per match produced by the number of accurate shots produced (with the averages for the entire league indicated by the red lines). Take a look at Arsenal compared to the other top teams. Clearly, Chelsea and Manchester United, for example, create about the same number of shots from fast breaks, but they're about 50% better in producing accurate shots. Or take a look at West Ham. While they were right around the league average in producing shots from fast breaks in the first half of the season, they didn't produce many accurate ones.
As before, these analyses come with the caveat that the patterns described here may not have held in the second half of the season as managers have adjusted to their teams' successes and failures on various dimensions of play. But given what we know from Sarah Rudd's (of Onfooty.com) calculations of the stability of metrics, it seems reasonable to assume that teams didn't all of a sudden grow new capabilities, though some may have tried to adjust how they employ them or pick up help in the January transfer window. Take a look at Aston Villa for example. Maybe they felt they needed Darren Bent because they had a sense of what kind of help they could use offensively.
To see how much this matters, I will take a look at goal creation from different match situations soon.
