With only six points separating Arsenal in second and Manchester United in sixth in this season’s English Premier League, a place in the top four may even come down to goal difference. As we are past the halfway mark of the season now, I thought it would be an appropriate time to take a look at the notion of consistency, and in particular how this season’s chance conversion rates compare to last season’s.
Conversion rates are typically calculated as a ratio of total goals scored over total chances, and have been a long established metric in the footballing world. Putting the ball away at the first time of asking will result in a better conversion rate, while squandering chances before scoring will result in a poorer conversion rate.
For this piece, I’m going to focus on teams from Europe’s “top five” leagues, namely the English Premier League, Spanish La Liga, German Bundesliga 1, Italian Serie A and French Ligue 1. I’ve pulled data from the 2nd of August 2015 to the 22nd of January 2017 to give a perspective of consistency over a season and half. So, let’s start by taking a high level look across all five leagues from last season and the current season so far, in order to help us distinguish between the “clinical” sides and the “wasteful” ones.
The above figures plot Goals (x-axis) and Chances (y-axis) for each team across Europe’s top five leagues, while the size of the circles illustrate conversion rate. The larger the circle, the better the conversion rate. To iterate this, I’ve plotted a white line down the middle of the graphics; teams above (to the left of) the line are more efficient (higher conversion rate/bigger circle) than the average, whilst teams below (to the right of) the line are less efficient (lower conversion rate/smaller circle). In other words, the closer a team is to the top left of the figure, the more clinical they are. Whilst the closer a team is to the bottom right, the more wasteful they are.
The most striking fact about last season (see 2015/16 graphic) is the attacking power of Barcelona, Real Madrid and PSG last season. This trio stand head and shoulders above the rest of the European clubs, thanks to scoring a combined total of 324 goals from a grand total of 945 chances. At the bottom end of the scale, Aston Villa’s woeful campaign is summed up their position on the scatter plot, sitting at the bottom of all of Europe’s top five league clubs with a mere 27 goals (albeit with a respectable conversion rate of 26% from their 104 chances). Villa are joined by Germany’s Hannover 96 (30% conversion rate), Spain’s Real Betis (29%), Italy’s Bologna (28%) and France’s Troyes (17%).
It is refreshing to see this season’s (see 2016/17 graphic) landscape differ significantly though, as the Barcelona and Real Madrid are joined by a host of Europe’s top clubs, including Arsenal, Chelsea, Liverpool and Napoli. Monaco have had a season to remember so far, outscoring everyone in Europe with a total of 60 goals from 228 chances, giving them a conversion rate of 26% (the best in Europe this season, way ahead of joint second place RB Leipzig and Sevilla’s 19%, who we’ll discuss in more detail later on).
Now let’s dive into each league specifically and take a closer look at each team’s performance over the two seasons:
English Premier League
Last season can be grouped into three clusters; (1) teams who scored 59 goals or more and finished in the top 10 (with the exceptions of Manchester United, Stoke and Everton), (2) mid-table teams who scored 34-48 goals (again barring Everton in this group), and (3) Aston Villa. Of the top four, Arsenal finished the season with the worst conversion rate (28% or 65 goals from 234 chances), whilst Manchester City lead the top four race of being most clinical with a conversion rate of 34% (71 goals from 208 chances). However, across the whole league, Liverpool topped the chart for being the most clinical (35%, 63 goals from 182 chances), while a special mention should go to Sunderland for their conversion rate of 35% coming through their 48 goals from 91 chances to stay up! All hail Defoe.
The current season already looks more dispersed, with two potential clusters emerging at the halfway point. Of the top group, Arsenal have apparently worked on their finishing from last season and now have the best conversion rate in the league (18%, 48 goals from 270 chances), whilst Chelsea are also looking like their old selves again (17% conversion rate, 45 goals from 269 chances). Tottenham and Man City maintain their consistent attacking form from last season and remain at the right end of the scatter, whilst current champions Leicester City drop to the bottom cluster (12% conversion rate, 24 goals from 192 chances), effectively swapping positions with Chelsea as many predicted they would. Jürgen Klopp’s Liverpool may have scored the most goals this season, but they fall just short of Arsenal and Chelsea with a conversion rate of 16% (51 goals from 317 chances).
The least clinical teams this season are Southampton (7% conversion, 19 goals from 263 chances) and Manchester United (10% conversion, 33 goals from 325 chances), whereas last season West Brom unfortunately had the worst conversion rate with 23% (34 goals from 147 chances).
Spanish La Liga
Barcelona and Real Madrid have always stood out in Spain’s La Liga. This is epitomised by last season’s graphic, where both teams form a cluster of their own thanks to scoring over a 100 goals each with a conversion rate of 34% and 37% respectively. However, last season saw Las Palmas top the conversion rate ranking with 38%, scoring 45 goals from their 120 chances. Indeed, while Barcelona may have looked like one of two deadly teams in La Liga, Granada beat their conversion rate (36%, 46 goals from 128 chances), whilst Sporting Gijon and Deportivo La Coruna matched the Catalan club’s conversion rate (40 from 118 and 45 from 134 respectively).
This season we again see a more dispersed pattern appearing, as although Barcelona (18%) and Real Madrid (17%) still lead the way for goals scored, Sevilla have been the most clinical, scoring 38 goals from 197 chances (19%). This is striking, as Sevilla had the fourth-worst conversion rate last season! Espanyol also join the top band with a conversion rate of 17% (25 goals from 147 chances), whilst newly promoted Leganes have the worst conversion rate with 9% (15 from 168).
German Bundesliga 1
Last season’s German Bundesliga 1 shows a similar pattern to Spain’s top league, Bayern Munich and Borussia Dortmund way ahead of the pack (conversion rates of 33% and 34% respectively). However, Gladbach had the best conversion rate in the league with 38% (67 goals from 177 chances). Bayer Leverkusen also boasted a better conversion rate than Bayern Munich with 34% (56 from 166), whilst Hertha matched them with 33% (42 from 126). Stuttgart and Ingolstadt shared the worst conversion rate of 28% (50 from 179 and 38 from 133 respectively).
The current season again looks more dispersed – Dortmund still top the league for goals scored (37 from 200) but RB Leipzig come into the fold, boasting the best conversion rate in the league (19%, 34 goals from 176 chances). Impressively, Hertha maintain their strong clinical performance in front of goal, and this time better Bayern Munich with a conversion rate of 18% (24 from 136), as do Mainz (17%, 26 from 152). Darmstadt 98 sit at the bottom of the table with 8% of their chances converted to goals, whilst Augsburg are joined once again by Ingolstadt (9% each).
Italian Serie A
Italy’s Serie A last season also appears to have two clusters, with Roma, Napoli and Juventus hitting the heights for goals scored. However, in terms of efficiency, Fiorentina sit at the summit, boasting 60 goals from 147 chances (41% conversion). Roma followed the Florence club Roma by scoring 82 goals from 208 chances (40%), whilst Sassuolo also boasted a better conversion rate than Juventus (39% versus The Old Lady’s 38%). Last season’s worst performers were Hellas Verona, who were relegated in the end, and Udinese, who managed to survive the drop (24%, 33 from 137 and 35 from 144 respectively).
This season we again see a more dispersed pattern, and whilst Napoli still top the league for goals scored, They hold the fourth best conversion rate at 15%, falling short to (1) Cagliari (18%, 31 from 175); (2) Juventus (16%, 40 from 252); and (3) Torino (16%, 38 from 245). Sassuolo can once again boast a league impressive conversion rate (14%, 30 from 212) so far beating last year’s most clinical team Fiorentina (13%, 33 from 245). Udinese are having a better season this time around, as the teams at the bottom of the conversion table are Pescara (7%, 13 from 184), Empoli (8%, 11 from 142), Crotone and Sampdoria (9%, 14 from 153 and 22 from 236 respectively).
France Ligue 1
Last season was all about PSG, who scored 102 goals from their 318 chances (32%). However, they were closely followed by Bastia (31%, 36 from 116), Nice (31%, 58 from 187) and Guingamp (30%, 47 from 155). At the other end of the table, relegated Troyes converted 17% of their chances (28 from 165), whilst Nantes (19%, 33 from 175) and Marseille (20%, 48 from 238), who had the second and third worst conversion rates, survived the drop. Interestingly, Reims were relegated despite boasting a very respectable league conversion rate of 28% (44 from 158), bettering that of both Nantes and Marseille.
This season we once again see a much more dispersed pattern, with Monaco setting impossibly high standards. They’ve so far managed 60 goals from their 228 chances, setting an unrivalled conversion rate of 26%, way ahead of Nice (16%, 35 from 216), PSG (15%, 41 from 282) and Lyon (14%, 36 from 258). This goes some way to explaining why people have had so much joy backing Monaco and Overs this season, while Guingamp are also having a fine campaign and are sitting in fifth place, again boasting a respectable conversion rate with 13% (27 from 208). Nantes haven’t appeared to worked on their finishing ability, as they sit at the bottom of the conversion rate table having converted only 7% of their chances (14 from 212), alongside Angers SCO (16 from 216).
So far in the current season, the leagues look a lot more dispersed than last season, with teams such as Sevilla and Leipzig coming in to shake up the status quo. This highlights how one summer can change so much in football; Sevilla held the fourth-worst conversion rate last season but now are the most clinical team in La Liga; Leicester drop to the bottom cluster of the Premier League, as their ability to find the net diminishes (or reverts to mean, depending on which line of thought you follow), whilst Arsenal now boast the best conversion rate in the league after being branded as “wasteful” last season1 and changing their team relatively little from last season.
Furthermore, Gladbach now have the fourth-worst conversion rate in the Bundesliga, and they’ve so far been unable to maintain their high finishing standards from last season. New boys RB Leipzig could be German football’s fairy-tale if they maintain their strong conversion rate. Whilst the big teams will always boast a strong conversion rate given the number of chances they create and quality of players they have. Finally, other teams such as Germany’s Hertha, Italy’s Sassuolo and France’s Guingamp have shown a consistently good conversion rate over the year and a half, meaning they should all continue to perform steadily.
So it seems conversion rates are a fickle mistress, because while they can tell us something of great value “in the moment” the difficulty comes when trying to predict conversion rates over time, especially when considering the impact transfers, injuries and managerial change can have on the performance of squads. Until we can accurately do that we have to treat this metric with some care, understanding that things may revert to mean over differing time periods but are likely to be impacted by far more random factors. For now we can assume as long as the squads remain relatively intact and little changes on the managerial front, then the conversion rates on display will not change too drastically between now and the end of the season. Indeed, in my next post I might just take a look into how line-up consistency correlates with chance creation and chance conversion.
Until then, anyone for a bet on Monaco to win Ligue 1, Arsenal to win the Premier League, or RB Leipzig to finish top two in Bundesliga 1?
Sagar Jilka (@DrSagarJilka)
* Correct at time of analysis