Stats review: Ability to avoid chances and saving efficiency

Part one of our stats review was about the Superliga teams offensive performances through the first 15 games.  This part, part two, will focus on the defensive side of the first 15 games. Like in the offensive analysis, we will focus on two parts: ability to avoid chances and saving efficiency.

We start with the ability to avoid chances. This is a very important part of assessing the true quality of the teams. The more chances you allow, the more goals you risk conceding. So this statistic is naturally very important. Our first proxy for chances allowed is total shots allowed. Once again we use data from Superliga.dk.

 

Our findings are pretty surprising, since the order is not replicating the current table as well as we would have expected. Our observations:

• FC Copenhagen are by far the best team in avoiding chances. FC Copenhagen has a strong backline with a lot of international experience so their position in top is not surprising. The margin is however a bit wider than expected: Esbjerg in second place has allowed 26 shots more than FC Copenhagen.
• Esbjerg’s second place is in harmony with their performances in spring where Esbjerg had several clean sheets (8 in 14 matches). Nevertheless it is a bit unexpected since Esbjerg have not been able to continue their clean sheet streak this autumn (only 2 in 15), but this could be due to other things than an increase in chances allowed.
• SønderjyskE are not allowing as many chances as you would expect from a team placed alone at the bottom.
• AGF and Viborg, two teams that were also struggling in the offensive ability to create chances, have allowed many chances so far. A pattern seems to emerge: these two teams are clearly not dominating their matches.
• OB are allowing a concerning amount of chances. If you think of it, their poor position in this category is not a huge surprise. They have been dealing with injuries, change of goalkeeper and fielding players out of their normal positions (mainly at left back).

Like in the offensive case, we are not completely convinced that looking at total shots is the best way of measuring chances. For instance if a team is playing a style where they allow many attempts from distances with very low scoring probability, this will give wrong indications from the data, since they are actually not allowing many real chances. In order to avoid some of this bias, we use total shots on target (SoT) allowed. This measure should be able to exclude many of the attempts without a real chance of scoring, but we admit that this is measure is by no means perfect. Here is the statistic through 15 rounds:

With this sorting, we get closer to the current league standing, which also indicates that this is probably a better proxy for chances allowed. We must highlight:

• FC Copenhagen’s advantage is eradicated. Our interpretation is that FC Copenhagen are typically the dominant team and they are also in the lead with respect to average ball position (56 %). An offensive approach makes them vulnerable to counter-attacks, which primarily result in bigger chances than attempts from the distance.
• FC Midtjylland and AaB’s current position matches their ability to avoid attempts.
• OB improve compared to the previous statistic, but are still giving away a lot of chances.
• Viborg’s amount of chances allowed is really upsetting especially when you combine it with our findings in part one where they were also at the bottom in the ability to create chances.

The second part of the analysis focuses on the saving efficiency. We define this as the saving percentage:

Saving% = Goals allowed/Shots on allowed

Like we pointed out in our last review, this is also a statistic that will regress to the mean (see Grayson). In other words, any difference from the league average in the saving percentage is mainly based on luck. Of course some keepers are better than others, why small differences between the clubs can occur.

What does the table tell us?

• OB and Viborg can count themselves lucky with the performance of their keepers and the inefficiency of their opponents. Viborg’s Peskovic and OB’s Toppel have also done a good job (okay, forget the last game from Toppel). These two teams cannot rely on keeping this high saving percentage and therefore have to limit the amount of chances allowed.
• Brøndby and FC Midtjylland have also acquired a pretty high saving percentage that will be difficult to keep up. In the case of Brøndby this is particular interesting, since their attackers are the most inefficient in the league. Fortunately for them, a good defensive efficiency has put them in a fine position.
• SønderjyskE and Esbjerg have the worst saving percentage. Here we also find the explanation for Esbjergs poor position despite a good ability to create and avoid chances. Keeper Rønnow has simply conceded too many goals. For SønderjyskE this statistic is encouraging, since a move toward the average should mean fewer goals allowed. Whether this is enough to get more points remains to be seen.

This was part two of our stats review. Our next review and final review will make a summary of our findings. We will introduce some new measures and use them to make predictions about the final outcome of the Superliga 2013/2014. Stay tuned.