Sunday, 25 February 2018

Passive & Aggressive Defensive Teams

One of the major drawbacks in quoting counting statistics in football is the varied time of possession enjoyed by teams.

I first wrote about this nearly seven years ago here when describing Stoke's incredibly disciplined approach to defending once you factored in the inordinate amount of time they spent doing it under Tony Pulis in the early days of their soon to be ending Premier League jaunt.

Defensive statistics have always been blighted by failing to account for opportunity.

It is impossible for a Manchester City defender to accumulate the volume of defensive actions made by say a WBA defender, simply because the new champions are only out of possession for around 30% of a typical game and that game only has around 58 minutes when the ball is in play.

WBA, by contrast are averaging just 40% of the total possession and ceding ~60% to the opposition.

Before we can make any meaningful descriptive attempt at a side's defensive set up, we need to make some kind of attempt to account for the unequal range of possession for each team and the amount of time that the ball spends on the pitch rather than in the stands.

We can also attempt to define where on the field a side is trying to dispossess their opponents.

Some teams are noted for the desire to press opponents higher up the pitch to create a turnover or slow down a developing attack, whereas others are more content to lie deep and only actively engage an opponent once they venture into their final third. 

Vertical distance from your own goal can be slightly misleading. If you challenge an opponent on the centre spot you are slightly closer to your own goal than if the event occurs also on the halfway line, but on the touchline.

All calculations have been made from the point of the challenge to the centre of the defending sides own goalline.

 The table above using Infogol data has counted the number of defensive actions, such as tackles, interceptions and clearances made by each team after 27 games of the current Premier League campaign.

These have been grouped by distance from the event to the centre of that side's own goal. Finally, these event numbers have been standardised to account for the actual time each side has been without the ball and a figure for defensive actions per 10 minutes of opposition possession has been calculated.

For example, Manchester City appears to have by far the least number of active attempts to disrupt or disposes an opponent in 2017/18, only making around 16 such attempts per 10 minutes of opponent possession.

So they appear happy to allow teams to circulate the ball, but they do make their most concerted efforts to intercede between 20 and 40 yards from the City goal.

In contrast, Liverpool are much more aggressive at trying to regain the ball, making over twice as many defensive actions per 10 minutes than City, as well as  engaging opponents almost once a minute at distances of 50 or more yards from Liverpool's own goal.

The final sparkline plot shows, not only the total volume of defensive actions per 10 minutes of opponent possession, but also where a side is most active in engaging their opponent.

A side's own goal is on the left of the plot and volume of actions take place further away from a side's own goal as you move towards the extreme right of the sparkline.

The majority of  the top six teams peak their defensive actions between 30 and 40 yards from goal, whereas the remainder of the league by a majority either chose or are forced to defend between 10 and 20 yards from goal.

The most prominent example of a top six team residing in a relegation threatened defensive mindset is Manchester United.

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