Feb 2, 2018
Feb 2, 2018

The importance of formation in soccer

The importance of formation in soccer

Expected goals can be used to analyse how effective specific formations are in a soccer match. This article explains why bettors need to understand the importance of formation when betting on the Premier League. Read on to find out more.

In my previous article, I looked at how expected goal (‘xG’) data can be broken down by speed of attack, and how that information can be used to guide your betting selections. The source of the data was understat.com, and the same website provides other breakdowns of xG statistics.

This article will look at formations. Once again I have focussed on the 14 current Premier League teams who have been in the division since the start of 2014/15.

These teams have utilised a total of 20 different formations between them. The obvious issue here is that formations can be open to interpretation. For instance when is a 3-5-2 all that different from a 3-4-1-2?

To weed out some of the slightly unusual formations, I have focussed on the eight which have been used for at least 3,420 minutes, as that is the length of one entire season for one team. This seems a good sample size to begin with. Here they are sorted by their expected goal difference per 90 minutes.

Formation and expected goal difference

Formation Minutes xG xGA xGD xG/90 xGA/90 xGD/90
3-4-3 3973 60.14 39.78 20.36 1.36 0.90 0.46
3-4-2-1 4762 76.62 56.30 20.32 1.45 1.06 0.38
4-2-3-1 76236 1186.49 930.23 256.26 1.40 1.10 0.30
4-1-2-1-2 5071 83.08 66.22 16.86 1.47 1.18 0.30
4-1-4-1 8419 120.23 106.52 13.71 1.29 1.14 0.15
4-3-3 20112 276.97 254.73 22.24 1.24 1.14 0.10
4-4-2 15141 238.06 227.23 10.83 1.42 1.35 0.06
4-4-1-1 5459 76.62 81.74 -5.12 1.26 1.35 -0.08

The top two on the table illustrate the earlier problem I highlighted. To all intents and purposes they are the same formation. We also have to factor in the strength of the teams using the formations as that will obviously impact how successful they are.

Chelsea won the title in 2016/17 by using a back three, and (obviously to a lesser extent) Liverpool had their best run in 2014/15 when playing three centre-backs. That won’t be the case for all teams though of course.

You can see the most common formation has been 4-2-3-1. As all 14 teams have used it in the past three seasons and all but two for at least 3,420 minutes in total, I’m going to take a closer look at that.

The following table shows each team’s expected goals difference per 90 minutes when playing 4-2-3-1, the same figures for all other formations, and they are sorted by the difference between the two.

Expected goal difference by team 4-2-3-1

Team 4-2-3-1 Minutes 4-2-3-1 xGD Per 90 Minutes Other xGD Per 90 Minutes Difference
Stoke 8560 -0.01 -0.51 0.50
Swansea 5820 -0.26 -0.75 0.49
Arsenal 8652 0.86 0.48 0.38
West Brom 4454 -0.10 -0.44 0.34
Leicester 755 0.26 0.05 0.20
Liverpool 1927 0.65 0.46 0.19
Everton 6363 0.09 -0.10 0.19
Southampton 5802 0.37 0.23 0.14
Man City 5523 1.04 0.91 0.12
Man United 4304 0.46 0.36 0.10
Crystal Palace 4557 -0.12 -0.16 0.05
West Ham 3788 -0.30 -0.15 -0.15
Tottenham 8691 0.45 0.70 -0.24
Chelsea 7040 0.52 1.05 -0.54

It’s important to note that three of the teams in the top four for improvement are still on a negative expected goal difference. They may perform better with a 4-2-3-1 formation than they normally would, but that’s certainly not to say their stats mean that they’d win. The numbers merely suggest that they’d have a better chance of coming out on top.

At the other end of the table, it seems 4-2-3-1 does not suit teams from London! Tottenham and Chelsea are in the top four for the amount of time spent playing in this formation, but they are not as effective as they have been when employing other tactics.

It’s also interesting that when you look at which formations teams have used for over 1,000 minutes. In the last three seasons, 4-2-3-1 has been the most effective for eight of them. Here are each team’s best tactical set ups for expected goals difference

Best formation for expected goals difference

Team Formation Minutes xG xGA xGD xGD/90
Man City 4-2-3-1 5523 117.67 54.1 63.57 1.04
Arsenal 4-2-3-1 8652 168.83 86.31 82.52 0.86
Man United 4-3-3 1441 24.02 11.06 12.96 0.81
Liverpool 3-4-3 1126 18.58 9.74 8.84 0.71
Chelsea 3-4-3 1837 22.24 11.21 11.03 0.54
Tottenham 4-2-3-1 8691 148.54 104.9 43.64 0.45
Southampton 4-2-3-1 5802 93.95 70.36 23.59 0.37
Everton 4-2-3-1 6363 89.5 83.25 6.25 0.09
Crystal Palace 4-1-4-1 1117 11.36 10.35 1.01 0.08
Leicester 4-4-2 6860 101.97 98.2 3.77 0.05
Stoke 4-2-3-1 8560 114.25 115.45 -1.2 -0.01
West Brom 4-2-3-1 4454 52.27 57.42 -5.15 -0.10
West Ham 4-1-2-1-2 1490 16.88 18.73 -1.85 -0.11
Swansea 4-2-3-1 5820 68.54 85.54 -17 -0.26

From a bettor’s perspective, one issue is that it is hard to know what formation a team is going to use in a particular match. It may be sensible to wait until the teams are announced before placing your bets.

If a team has used a formation for a while though, it’s likely they’ll stick with it. For instance, Arsenal have had seasons where they have started with a 4-2-3-1 formation in every single league game. This type of information is also widely available on the internet, so you can get a good idea in advance of a match, even if you can never be entirely sure.

As much as this information can be useful, like any insight when applied to betting it is not without its flaws. A team may have used a formation under a previous manager, and the new boss may have no intention of employing it.

There is also not much data for some formations. Two of them (4-2-4-0 and 4-1-3-2) have been used for less than 90 minutes by the 14 teams across the last three seasons. You might know a team is going to line up that way, but there may not be data available to guide you.

Equally, different formations will be used for different purposes. Teams occasionally switch to formations with three defenders when chasing the game for example. Game state will therefore have an impact on the xGD.

Perhaps most importantly, soccer is not just about what formation a team plays, but how they fare against different formations. Player movement is key to having success in soccer. It’s not as if the players remain in rigid lines like they do in a game of table football.

Every formation has its flaws and weaknesses. Teams have had success with a back three, for instance, but opposing teams can exploit space by playing behind their wingbacks. Despite that, a little knowledge surrounding how teams perform when using different formations is no bad thing when it comes to selecting your bets.

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