Sonntag, 12. April 2015

How to read a Goalimpact Chart?

Following the updated algorithm and the latest Top-50 players list, we received a lot of questions to individual players and on how to read the chart. Let's answer both in one post.

Zlatan Ibrahimovic

Easily the most requested player following the Top50 post. Probably, because he was not on the list. That doesn't mean that Goalimpact isn't rating him, he is just not in the Top50. Main reason is that he dropped out of the list due to aging. Here is the chart.

The thick line shows the Goalimpact at that time. This is the original estimate not using any future games. Clearly, with hindsight, we may give him another rating, because his team outperformed or underperformed original expectations. The expectations on how good a Zlatan will be in future, are derived from the Peak Goalimpact (thin dashed line) and the aging curve of field players.

If the team results of all of Zlatan's games are better than expected by his Goalimpact, the PeakGI line will raise. It will do that whenever the player overachieves original expectations, independent if he passed his peak already or not. In the recent year, for example, his PeakGI raised because his performance dropped less than we would have expected given the typical aging effect in football. Since 2011, the peak rose nearly 15 points. Without that raise, his Goalimpact would have been 15 points lower than it is today, so 140 instead of 154 points.

To summarize, Zlatan is a world-class player that is gradually weakening due to aging. But this aging process is much slower with him than with the average football player. His current performance still is outstanding at 154.

Theo Walcott

The high rating of Theo Walcott raised some virtual eyebrows on Twitter. So this is how his chart looks like:

Theo was rated "world-class one day" since he was very young. Given his young age, he was still rated as "ok for Premier League, but not outstanding". But this is his actual performance and not his "potential performance" or "talent", which both were rated as very high. Walcott delivered as expected until 2012. Therefore his PeakGI was more or less stable and the Goalimpact rose along expectations given the aging curve. From 2012 on, the team strongly outperformed expectations when he played and hence his PeakGI rose consistently until it reached a level of about 190 when match outcome and Goalimpact were in agreement.

Back to the Twitter question of why Walcott is rated that good: Because the team consistently outperformed prior (already very high) expectations with him on the field.

Cristiano Ronaldo

"Cristiano Ronaldo is only 21st? Lol, he would walk into any team of the world" was a typical comment. We understand the critic because he is one of the best players of the world (also in according to Goalimpact) and many see him as the best (also Goalimpact before the change of the algorithm). So why did he drop in the new algorithm?

He actually didn't drop in the new algorithm, he maintained the world-class level he obtained in his Manchester United times seamlessly at Real Madrid. Real's performance with him on the field was fully in line with these very high expectations and thus there was no need to raise or lower the rating.

"Yes, ok, but he was rated higher in the old version". True, the reason is that Goalimpact adjusts expectations for all players of the field. The new version rates Karim Benzema higher than the old. This, in turn, raises the needed outcome for all his team mates to increase their respective scores. Hence, with Benzema rated higher, his team mates including Ronaldo were rated lower. That said, Ronaldo is rated as absolute world-class and would also according to Goalimpact walk easily into any team of the world.

Karim Benzema

So? And why is Benzema that good?

We can't answer that. Goalimpact just measures how good a team plays with the player on the field. It can't tell why a player is adding to the team success., because it does not even look on what he is doing. It just relates the team success to the player being present on the field. If we define a "good player" as a player that make his team have a very good goal difference, then Benzema is extraordinarily good.

Top50 Football Players - April 2015 Edition

It is nearly one year ago that we published the last "Top50" list and hence we should expect many changes. But as we also just updated the algorithm there are even more changes and the list is a bit difficult to digest. Here are the main findings so far

  • Most players on this list have been rated high one year ago in the previous version of the algorithm already. On rank 17, Georginio Wijnaldum is the first player that hasn't been Top100 before already.
  • Compared to the old algorithm, the players seem distribute now stronger over leagues and teams. Previously, it was very much focused on the big teams.
  • In the old list, there has been a few players with exceptionally high Goalimpact. The new list doesn't have skill gaps apart of the one that separates Thomas Müller from the rest of the world. This results in many players having a higher Goalimpact and only few players a lower in this list. Overall, the rating scale didn't change. The average is still 100.
  • Despite Austrian leagues having suffered a lot from the new league adjust in the algorithm, two Red Bull Salzburg players made it to this list. Three, if you consider Kampl's breed.
  • Can somebody please buy Vladimir Stojković for 1M€ and let him play in a league where we can watch him to access if he is still really that good?
  • Former Top50-Players no longer that dropped out of the Top100. That is partly due to the change in algorithm, partly due to age or lower performance: 
    • Philipp Lahm (156.94)
    • Xabi Alonso (156.52)
    • Vincent Kompany (154.17)
    • Gianluigi Buffon (153.86)
    • Scott Brown (152.23)
    • John Terry (150.84)
    • Patrice Evra (145.12)
    • Wesley Sneijder (142.09)
    • Ashley Cole (141.81)

Where curious to hear your thoughts.

Rank Player Team Goalimpact Age PeakGI Nationality Previous
GI Diff
1 Thomas Müller Bayern München 217.30 25.58 218.49 Deutschland 8 +44
2 Mesut Özil Arsenal FC 201.95 26.50 202.86 Deutschland 15 +38
3 Karim Benzema Real Madrid 199.45 27.25 201.99 Frankreich 18 +41
4 Lionel Messi FC Barcelona 199.33 27.75 202.83 Argentinien 4 +17
5 Robert Lewandowski Bayern München 198.36 26.58 199.57 Polen 37 +53
6 Cesc Fàbregas Chelsea FC 196.06 27.92 199.83 Spanien 5 +17
7 Theo Walcott Arsenal FC 192.75 26.08 192.83 England 57 +52
8 Manuel Neuer Bayern München 191.69 29.00 192.79 Deutschland 11 +22
9 Luiz Gustavo VfL Wolfsburg 190.94 27.67 194.28 Brasilien 55 +49
10 Marcelo Real Madrid 189.24 26.92 190.99 Brasilien 29 +39
11 Busquets FC Barcelona 187.84 26.67 189.24 Spanien 26 +35
12 Fraser Forster Southampton FC 185.76 27.00 187.97 England 65 +46
13 Pedro FC Barcelona 185.10 27.67 188.41 Spanien 49 +42
14 Mario Götze Bayern München 183.74 22.83 193.00 Deutschland 36 +37
15 Toby Alderweireld Southampton FC 183.06 26.08 183.22 Belgien 54 +41
16 Piqué FC Barcelona 182.54 28.17 186.72 Spanien 22 +27
17 Georginio Wijnaldum PSV Eindhoven 182.11 24.42 186.33 Niederlande 185 +53
18 Kevin Kampl Borussia Dortmund 182.06 24.50 186.04 Slowenien 70 +43
19 Stefan Ilsanker RB Salzburg 181.49 25.83 181.83 Österreich 106 +47
20 Jeremain Lens Dinamo Kiev 181.21 27.33 183.88 Niederlande 66 +41
21 Cristiano Ronaldo Real Madrid 180.74 30.17 188.42 Portugal 1 -16
22 Gaël Clichy Manchester City 180.69 29.67 187.05 Frankreich 21 +25
23 Andriy Pyatov Shakhtar Donetsk 179.64 30.75 179.77 Ukraine 69 +40
24 Antonio Valencia Manchester United 178.31 29.67 184.63 Ecuador 310 +55
25 Wayne Rooney Manchester United 178.19 29.42 184.20 England 9 +6
26 Mats Hummels Borussia Dortmund 178.15 26.25 178.73 Deutschland 23 +23
27 Andreas Ulmer RB Salzburg 178.01 29.42 183.99 Österreich 61 +37
28 Ángel Di María Manchester United 177.48 27.17 179.70 Argentinien 35 +30
29 Bastian Schweinsteiger Bayern München 177.41 30.67 188.08 Deutschland 3 -6
30 Eden Hazard Chelsea FC 177.36 24.25 181.99 Belgien 122 +45
31 Arturo Vidal Juventus 177.05 27.83 180.73 Chile 48 +34
32 Nani Sporting CP 176.99 28.33 181.47 Portugal 117 +44
33 Arjen Robben Bayern München 176.72 31.17 190.43 Niederlande 19 +19
34 Petr Čech Chelsea FC 175.97 32.83 179.86 Tschechien 17 +17
35 Daniel Agger Bröndby IF 175.88 30.33 184.44 Dänemark 182 +47
36 Gregory van der Wiel Paris Saint-Germain 175.85 27.17 178.14 Niederlande 27 +24
37 Jonny Evans Manchester United 175.51 27.25 177.97 Nordirland 213 +48
38 Douglas Dinamo Moskva 175.01 27.25 177.42 Niederlande 125 +43
39 Toni Kroos Real Madrid 174.34 25.25 176.33 Deutschland 68 +35
40 Salomon Kalou Hertha BSC 172.43 29.67 178.75 Elfenbeinküste 50 +30
41 Joe Hart Manchester City 172.10 27.92 173.80 England 132 +40
42 Vladimir Stojković Maccabi Haifa 171.99 31.67 173.41 Serbien 283 +48
43 Willian Chelsea FC 171.32 26.67 172.58 Brasilien 58 +30
44 Kwadwo Asamoah Juventus 170.90 26.33 171.51 Ghana 139 +40
45 Ezequiel Garay Zenit St. Petersburg 170.88 28.50 175.51 Argentinien 124 +39
46 Alexis Sánchez Arsenal FC 170.69 26.25 171.24 Chile 75 +33
47 Alex Song West Ham United 170.69 27.58 173.77 Kamerun 64 +30
48 Jérôme Boateng Bayern München 169.29 26.58 170.43 Deutschland 33 +20
49 Danijel Subašić AS Monaco 169.06 30.42 169.38 Kroatien 340 +47
50 Javier Mascherano FC Barcelona 168.94 30.83 180.47 Argentinien 14 +4

Georginio Wijnaldum picked up in summer 2011 when he
moved to PSV. Since then, it has been a continues increase
to world-class level. Not only in Goalimpact terms, but also
shown by a third place in the World Cup and the this years' 
victory of the Dutch league.

Donnerstag, 9. April 2015

New Algorithm Released

It has been silent on the blog lately, but it wasn't a quite time. We have been busy putting together a new version of the algorithm that promises a better discriminatory power between good and better players. The main change was to improve the comparability of the Goalimpact values between the different leagues.

What was the issue?

Previously, some remote leagues such as New Zealand or Austrian amateur leagues weren't closely enough related to core leagues to have them rated correctly compared to each other. This resulted in overrated players from those leagues showing up in some top player lists that clearly didn't belong there. This could be solved easily by filtering all players in those leagues.

More worrying, however, was if any of those player did move to another league. He will then show up in reports with the high rating and it will be difficult in all cases if the rating was just earned by some season in a missvalued league.

The solution

More care is now taken to ensure that all information on the relative value of the leagues is properly reflected in the player ratings. This is done in a moderate, very careful way. In particular, there is no "Leaguefactor" and hence we do not expect any jumps of rating if a player moves from one league to another. Also promoted teams are expected to be better ranked compared to the other teams. In the old algorithm they tended to be slightly overvalued.

The current status

The new model is released and the database is fully updated. Any results we publish from now on will be based only on the new version. The update is brand new and hence we didn't have the time to check all results so far. So in the coming days and weeks we will post some slicing of the data to get and give a feeling of the new model. While we are confident that the new model is an improvement over the old, it is still an exiting journey into the unknown for us.

As a first glimpse, here are the best teams according to the new algorithm. The values are minute-weighted averages of all players that played that season for the team. Hence it may not entirely reflect the current team composition. E.g. Dortmund now is probably a bit better due to the signing of Kevin Kampl in the Winter break and Red Bull Salzburg accordingly a bit weaker.

Team Goalimpact Peak GI Min Max
Bayern München 168.1 176.8 108.1 217.3
FC Barcelona 159.0 167.1 108.5 199.3
Real Madrid 157.5 164.1 103.6 199.5
Manchester City 151.1 159.1 97.3 180.7
Chelsea FC 148.5 158.5 96.7 196.1
Manchester United 143.9 153.6 73.8 178.3
Borussia Dortmund 142.3 147.0 78.0 182.1
Paris Saint-Germain 140.2 151.2 76.8 175.9
Arsenal FC 139.3 148.3 83.8 202.0
Juventus 137.7 148.9 85.6 177.1
VfL Wolfsburg 136.6 143.3 103.1 190.9
Atletico Madrid 136.4 146.4 103.5 160.1
Zenit St. Petersburg 135.0 143.4 78.2 170.9
Dinamo Kiev 132.7 138.1 87.0 181.2
Southampton FC 131.5 137.8 97.8 185.8
Shakhtar Donetsk 130.5 140.6 81.0 179.6
Liverpool FC 130.2 141.8 91.1 165.5
Bor. Mönchengladbach 128.6 136.0 97.4 164.5
FC Porto 128.2 136.2 95.7 166.7
CSKA Moskva 128.2 139.9 83.4 167.1
RB Salzburg 127.6 143.9 89.1 181.5
SL Benfica 127.6 137.6 75.1 147.7
Tottenham Hotspur 126.5 133.8 78.5 159.5
SSC Napoli 125.3 132.1 97.0 159.4
Valencia CF 125.1 133.7 93.3 151.4
AS Monaco 124.6 138.4 96.0 169.1
Bayer Leverkusen 124.5 137.5 96.7 156.3
Dinamo Moskva 124.2 130.7 70.5 175.0
PSV Eindhoven 123.3 136.1 84.5 182.1
ACF Fiorentina 123.2 133.2 89.3 162.5
Everton FC 123.0 136.4 68.3 150.5
Celtic FC 122.6 130.4 76.4 159.6
Sevilla FC 122.3 130.2 91.9 142.3
AS Roma 121.9 135.5 84.2 159.3
Sparta Praha 121.9 131.0 70.5 151.3
FC Schalke 04 121.9 133.4 63.7 162.4
Sporting CP 121.8 128.9 97.7 177.0
AC Milan 121.7 129.6 94.3 166.3
1899 Hoffenheim 121.3 128.2 86.1 153.1
Swansea City 121.0 126.0 76.7 132.2
Viktoria Plzen 120.3 127.4 64.8 144.1
AFC Ajax 119.9 134.7 83.6 152.2
AS Saint-Etienne 119.8 124.9 89.9 142.4
Hamburger SV 119.2 127.7 83.0 143.7
Guangzhou Evergrande 119.0 124.6 90.3 146.0
Hertha BSC 118.8 124.7 93.2 172.4
Inter 118.8 129.0 69.7 151.8
Lazio Roma 118.7 130.5 88.6 154.8
Olympique Lyon 118.4 131.2 84.4 144.3
West Ham United 117.6 124.0 85.2 170.7

Sonntag, 11. Januar 2015

The Best And Worst Champions League Finalists Ever

Inspired by Rob Brown's following tweet, we look at the best and worst Champions League finalist ever.
To answer that question, we should first define what is good and what is less good. Obviously, on this blog our measure will be the average Goalimpact of the team. However, because we don't really know which players were available in the games, we take the average of the starting XI only. Also we need to define what we mean by 'Champions League'. We included predecessor, the European Champion Clubs' Cup

Before we answer Rob's question, let's look at the best finalists rather than worst finalists.

Rank Season Team Goalimpact PeakGI Win
1 2013/2014 Real Madrid 147.7 152.9 yes
2 2012/2013 Bayern München 145.7 152.7 yes
3 2010/2011 FC Barcelona 144.5 152.3 yes
4 2008/2009 Manchester United 140.1 151.3 no
5 2007/2008 Chelsea FC 139.2 150.4 no
6 2007/2008 Manchester United 138.9 146.5 yes
7 2011/2012 Bayern München 136.8 146.7 no
8 1995/1996 AFC Ajax 135.3 150.3 no
9 1973/1974 Bayern München 134.3 139.9 yes
10 2010/2011 Manchester United 133.8 150.5 no
11 1994/1995 AFC Ajax 131.9 147.4 yes
12 1993/1994 FC Barcelona 131.8 139.6 no
13 2009/2010 Bayern München 131.3 142.5 no
14 2012/2013 Borussia Dortmund 131.2 135.4 no
15 2005/2006 FC Barcelona 130.6 138.5 yes
16 2001/2002 Real Madrid 130.3 137.1 yes
17 2005/2006 Arsenal FC 129.8 140.9 no
18 2008/2009 FC Barcelona 129.2 142.6 yes
19 1982/1983 Hamburger SV 129.1 137.3 yes
20 1974/1975 Bayern München 129.1 134.2 yes

As we can see, the answer to the opposite of Rob's question is "Manchester United 2008/2009". That is the best finalist not to win the cup. The second best team not to win is Chelsea FC that lost against ManU in a penalty shoot-out. In Goalimpact terms, the teams' ratings were to close to call a winner, too.

Now, let's look at the other end of that table.

Rank Season Team Goalimpact PeakGI Win
99 1961/1962 SL Benfica 106.1 119.2 yes
100 1959/1960 Eintracht Frankfurt 106.0 118.5 no
101 1975/1976 AS Saint-Etienne 105.3 111.1 no
102 1979/1980 Nottingham Forest 105.2 114.8 yes
103 1973/1974 Atletico Madrid 105.1 118.7 no
104 1967/1968 SL Benfica 104.8 113.8 no
105 1955/1956 Stade Reims 104.6 114.8 no
106 1969/1970 Feyenoord 104.4 111.7 yes
107 1967/1968 Manchester United 103.8 121.2 yes
108 1987/1988 PSV Eindhoven 103.3 113.4 yes
109 1977/1978 Club Brugge KV 103.2 113.7 no
110 1978/1979 Nottingham Forest 102.9 113.4 yes
111 1985/1986 Steaua Bucuresti 102.8 110.6 yes
112 1957/1958 AC Milan 102.8 114.8 no
113 1988/1989 Steaua Bucuresti 102.4 115.1 no
114 1956/1957 ACF Fiorentina 102.0 109.5 no
115 1987/1988 SL Benfica 101.9 111.2 no
116 1986/1987 FC Porto 101.6 111.8 yes
117 1970/1971 Panathinaikos 100.5 110.7 no
118 1978/1979 Malmö FF 94.0 110.4 no

That answers the question. The worst team ever to win the cup was the FC Porto in season 86/87. But that was in the European Champion Clubs' Cup in which winning for a less good team was more likely. If we restrict the list to Champions League only, we end up with

Season Team Goalimpact PeakGI Win
1994/1995 AC Milan 117.89 129.90 no
2003/2004 AS Monaco 117.48 122.08 no
1992/1993 Olympique Marseille 116.52 127.82 yes
1995/1996 Juventus 115.28 127.88 yes
2001/2002 Bayer Leverkusen 114.98 119.15 no
1999/2000 Real Madrid 112.71 126.38 yes
1993/1994 AC Milan 111.98 123.98 yes
2000/2001 Valencia CF 111.38 126.06 no
1999/2000 Valencia CF 110.59 122.10 no
2003/2004 FC Porto 110.48 118.31 yes

And hence, according to Goalimpact at least, the worst team ever to win the Champions League was FC Porto in 2003/2004. They were lucky to play against on of the other ten weakest finalists in the competition AS Monaco. Clearly, those times the concentration of top players on a small number of clubs wasn't that advanced already as it is in Europe today. Therefore, there was still a chance that too underdogs could reach the final. This seems unthinkable today.

Mittwoch, 17. Dezember 2014

Liverpool's Transfers Revisited

Duncan Castles writes on Bleacher Report about the dismal transfer record of Liverpool FC under Brendan Rodgers' management. Part of the critic is the overly reliance on an analytic model in scouting that selected bad players or rejected good. For example, Castles points out that Liverpool rejected Sadio Mane on the ground that the model said he isn't good enough for Premier League. Mane now plays for Southampton FC and is proving the opposite. Given that Goalimpact predicted Sadio Mane to be good enough a full year and 4 Mio. Euros before Southampton signed him, let's check what Goalimpact tells us on the other transfers made. Here is the full roster. Rodgers' transfers are marked yellow.

Liverpool FC

PlayerGoalimpactPeak GIAgeLast National TeamNo. GamesNo. Minutes
Simon Mignolet105.7114.726.8Belgien24122449
Danny Ward74.1131.521.4Wales [U21]9837
Brad Jones85.686.332.712111212
Lloyd Jones79.2112.319.2England [U19]11970
Mamadou Sakho109.1111.924.8Frankreich21518002
Dejan Lovren118.5119.825.4Kroatien22519680
Glen Johnson125.3135.630.3England40936172
Ryan McLaughlin89.9113.220.2Nordirland [U19]302541
Kolo Touré129.7163.233.7Elfenbeinküste50942986
Michael Williams85.2119.119.1Wales [U21]2138
Alberto Moreno108.4119.022.4Spanien [U21]836965
Manquillo96.7117.520.6Spanien [U21]403270
Jon Flanagan112.7125.321.9England [U20]473714
Martin Škrtel105.5113.530.0Slowakei34330267
José Enrique108.7115.328.8Spanien [U21]25821950
Steven Gerrard130.6170.434.5England75163042
Suso91.0109.021.0Spanien [U21]805177
Coutinho101.0111.322.5Brasilien [U20]1439443
Cameron Brannagan64.9104.118.64344
Joe Allen112.9115.824.8Wales23716932
Lucas Leiva108.7113.927.9Brasilien28221344
Adam Lallana114.4115.926.6England27521777
Emre Can109.2128.120.9Deutschland [U21]1249880
Jordan Henderson122.5126.124.4England26921103
Jordan Rossiter72.1115.117.77537
Raheem Sterling102.0126.620.0England1218475
Lazar Marković117.3137.120.8Serbien1268203
Daniel Sturridge121.3123.025.3England21713254
Fabio Borini94.7100.423.7Italien [U21]1247798
Rickie Lambert103.5132.132.8England26621835
Mario Balotelli106.9110.824.3Italien25916740

First thing to note is that about half of the team was signed by him. Apart from Borini, all seem to be good enough to play Premier League, also Coutinho and Manquillo will need some more development.

Some of the players are quite young and expected to improve significantly in the coming seasons. Given their potential, they were not bad signings as such. Even though they are maybe not good enough to qualify for Champions League this season, some are expected to be develop into that level (>120). Due to this fact, one can argue that the prices paid were too high. You'd expect bigger talent or further developed players for that money. Even in England.
Kolo Toure is a very good player, but well beyond his peak. His aging
is going to accelerate soon.

Especially in attack, the signings were not very convincing. We have no information on the factors that lead to the signings, but the two signings from Italy might point to a malfunctioning adjustment for league strength or opposition in general.

Mignolet is for sure a good keeper, but for 10 million Euros you can easily sign better ones. Brad Jones that played against ManU the other day, doesn't live up to Premier League standards.

Optimal XI

Ignoring all tactical considerations (no, this is not a recommendation), just picking by Goalimpact, leads to the following starting XI plus bench.

PlayerGoalimpactPeak GIAgeLast National TeamNo. GamesNo. Minutes
Daniel Sturridge121.3123.025.3England21713254
Steven Gerrard130.6170.434.5England75163042
Simon Mignolet105.7114.726.8Belgien24122449
Dejan Lovren118.5119.825.4Kroatien22519680
Joe Allen112.9115.824.8Wales23716932
Glen Johnson125.3135.630.3England40936172
Adam Lallana114.4115.926.6England27521777
Kolo Touré129.7163.233.7Elfenbeinküste50942986
Jordan Henderson122.5126.124.4England26921103
Jon Flanagan112.7125.321.9England [U20]473714
Lazar Marković117.3137.120.8Serbien1268203
Mamadou Sakho109.1111.924.8Frankreich21518002
Lucas Leiva108.7113.927.9Brasilien28221344
Emre Can109.2128.120.9Deutschland [U21]1249880
José Enrique108.7115.328.8Spanien [U21]25821950
15 Player Average

This is good enough to end up sixth in Premier League, so currently Liverpool is underperforming. But even if they weren't, the team isn't good enough to reasonably expect to qualify for Champions League. Comparing this to the Champions League game against Basel, only Škrtel, Sterling, Coutinho and Lambert weren't first choice players according to Goalimpact. Still Basel (113.6) even fielded a slightly better team than Liverpool (113.1) in that game. This again underscores the fact that the team doesn't live up to Champions League ambitions.


If the ambition of Liverpool FC is to qualify for Champions League the players bought don't live up to that objective. Whilst only Borini would be outright rejected as a EPL transfer target by Goalimpact, most are more suitable for a team in the upper midfield of the league table than for a team with Champions League ambitions. In fact, of all new players only Toure and Sturridge are already as of today above the target Goalimpact of 120. Can and Markovic are expected to be well above the target level in future. In case of Markovic that is very soon, Can will take another year or so. Given the money spent on the transfer market, better far options would have been available.