CIES Football Observatory Monthly Report n°40 - December 2018 Competitive balance: a spatio-temporal comparison Drs Raffaele Poli, Loïc Ravenel and Roger Besson 1. Introduction Competitive balance is a crucial issue for the whole of collective sports. Football is no ex- ception. American professional sport is even structurally organised to avoid too great an imbalance between teams. From a commer- cial perspective, the basic assumption is that uncertainty favours spectacle and revenues. The question of the balance of forces at play also has a moral dimension. It notably raises the issue of the equality of chance. A com- petitive balance allows a greater number of teams to attain victory, including those from countries or towns that are on the margins economically. However, competitive imbal- ance undermines the principle of uncertainty in sport. The 40th Monthly Report of the CIES Football Figure 1: study sample Observatory analyses competitive balance from a spatio-temporal perspective. The sam- - leaes ple includes 24 European competitions over a E1 remer eae (20080-201/08) (matches) 800 period of ten seasons between 2008/09 and ES1 a a (20080-201/08) 800 2017/18. The first part focuses on the league FR1 e 1 (20080-201/08) 3'799 [ER1 nesla (20080-201/08) 00 rankings at the end of the regular season, while IA1 Sere (20080-201/08) 800 the second analyses the results per match. Other omestc leaes [A1 nesla (20080-201/08) 1800 E1 Frst Dvson (20080-201/08) 208 DE1 Sperla (20080-201/08) 20 E2] Champonshp (20080-201/08) 20 FI1 Veasla (200-2018) 148 FR2] e 2 (20080-201/08) 800 [ER2] 2 nesla (20080-201/08) 00 I2] Sere (20080-201/08) 420 ED1 Erevse (20080-201/08) 00 OR1 Elteseren (200-2018) 2400 OR1 rmera a (20080-201/08) 24 O1 Estralasa (20080-201/08) 280 RS1 remer eae (20080-201/08) 22 [SCO1 remershp (20080-201/08) 2280 [SI1 Sper eae (20080-201/08) 182 [SE1 llsvensan (200-2018) 2 R1 Sper (20080-201/08) 02 Eropean compettons EFA C] Champons eae (20080-201/08) 120 EFA E] Eropa eae (20080-201/08) 18 Total 4 1 Monthly Report 40 - Competitive balance: a spatio-temporal comparison 2. Imbalances by season Figure 2: % of points of the champions and the three top ranked clubs, 22 leagues Numerous approaches are possible to meas- ure competitive balance over the course of a season. In order to maintain concision and Champions simplicity, two indicators reflecting the level of 76.0% 74.5% 74.2% 75.2% 72.9% 73.6% 72.6% domination of the top teams were retained for 71.2% 72.1% 71.6% this report. They are the percentage of points achieved by the club having finished the regular 67.3% 67.6% 68.2% 68.6% 66.6% 65.9% 66.1% 67.0% 66.5% season at the top of the rankings, respectively 65.4% Top 3 by the teams ranked in the top three places. The analysis excludes the eventual point pen- 200 2010 2011 2012 201 2014 201 201 201 2018 alties attributed to clubs. For the two indicators, the results show the trend towards a greater competitive imbal- Figure 3: % of points of the champions and the ance. The percentage of points obtained by the top three ranked clubs, big-5 champions increased from 72.3% during the first lustre taken into account to 74.5% during the latter. The average proportion of points for Champions 82.0% 83.3% the three top ranked teams has also increased 80.8% 80.2% 81.3% between the two periods: from 66.3% to 67.6%. 78.2% 77.1% 74.3% In the two cases, a new record was set during 73.4% 73.3% 74.4% 74.9% the last season analysed. 72.9% 70.6% 70.7% 71.5% 68.9% 69.2% 70.1% 67.2% The same analysis at the level of the big-5 Euro- Top 3 pean leagues shows that the level of imbalance is even more apparent and on the increase. 200 2010 2011 2012 201 2014 201 201 201 2018 During the 2017/18 season, big-5 leagues cham- pions achieved a record of 83.3% of points. This proportion is 10% greater than that measured in 2008/09. The average percentage between the first and last lustre studied increased from 76.0% to 80.8%. The analysis for the clubs ranked in the top three places shows the same trend towards increasing imbalance. 2 Monthly Report 40 - Competitive balance: a spatio-temporal comparison The spatial comparison allows for the high- Figure 4: average % of points of champions, by lighting of the differences between champion- league ships. At one extreme, the clubs having won Total 200-1 2014-18 Evolton the Portuguese top division obtained 84.4% of OR1 84.4 81 83.7% -14 possible points. At the other, the champions ES1 827% 84.6% 80.9% -3.7% of the French second division only achieved SCO1 798 77.0 826% +5.6% 64.4% of points. In 16 out of 22 leagues, the ER1 79.3% 75.7% 82 +72 percentage of points obtained by champions ED1 78 76.7% 800% +3.3% went up between the first and last five seasons ITA1 77.6% 73.5% 818 8 studied. The three greatest increases were re- E1 77.3% 76.1 784 +2 corded in the big-5 leagues: Ligue 1 (+10.0%), FR1 75.0 700% 800% +100% R1 741% 73.4 74.9% +1 Serie A (+8.3%) and Bundesliga (+7.2%). E1 73.4 75.7% 11 -4.6% OR1 28 11 74.5% +3.4 SI1 27% 708 4.6% +8 DE1 2 1 73.0 +11 RS1 17% 11 22 +11 SE1 708 69.3% 22 +2 FI1 0.4% 70.7% 701% -0.6% A1 701% 678 24 4.6% ER2 67.7% 69.6% 65.9% -3.7% E2 67.7% 66.1 69.3% +2 O1 8 84 65.1 -3.3% I2 4.6% 8 65.4 +16% FR2 4.4 16% 672 +5.6% 3 Monthly Report 40 - Competitive balance: a spatio-temporal comparison 3. Imbalances by match Figure 5: average goal difference per game, 24 competitions Competitive balance can also be measured at match level. This kind of analysis has the ad- vantage to allow for the inclusion of interna- tional competitions such as those organised by 1.355 1.357 1.342 UEFA: the Champions League and the Europa 1.327 1.322 1.315 1.312 1.312 League. In the two cases, only the matches 1.289 played from the group stages on were included 1.304 in the calculations. The average goal gap per game and the per- 200 2010 2011 2012 201 2014 201 201 201 2018 centage of matches where there was a goal difference of three or more are particularly pertinent indicators to measure competitive balance at match level. The results here also Figure 6: % of matches with a goal gap of three indicate a trend towards imbalance. The goal or more, 24 competitions difference per match went up from 1.309 for the first five seasons studied to 1.338 for the last five. The percentage of matches with a goal difference of three or more also increased 15.8% 15.8% between the same periods: from 14.3% to 15.8% 14.6% 14.8% 14.4% 14.5% 15.3%. In the two cases, the highest value was 13.8% recorded during the last season studied. 14.2% 14.4% 200 2010 2011 2012 201 2014 201 201 201 2018 4 Monthly Report 40 - Competitive balance: a spatio-temporal comparison The same trend towards a greater imbalance Figure 7: average goal difference per game, was measured at the level of the five major big-5 European championships. While the values for the 2017/18 season are not the highest ever 1.464 recorded, the averages between the first and 1.429 the last of the two lustres studied are explicit. The goal difference per match has risen from 1.363 1.408 1.333 1.325 to 1.400 and the percentage of matches 1.373 with a goal gap of three or more went up from 1.329 1.323 14.7% to 16.7%. 1.294 1.304 200 2010 2011 2012 201 2014 201 201 201 2018 Figure 8: % of matches with a goal gap of three or more, big-5 18.5% 18.0% 17.0% 16.0% 16.3% 15.2% 13.9% 14.4% 13.8% 13.9% 200 2010 2011 2012 201 2014 201 201 201 2018 5 Monthly Report 40 - Competitive balance: a spatio-temporal comparison Over the ten seasons studied, the biggest av- Figure 9: average goal difference per game, by erage goal difference per match was measured competition at the level of the UEFA Champions League: Total 200-1 2014-18 Evolton 1.58 goals. The premier competition of Europe- EFA C 18 1.40 18 021 an football is also that presenting the highest ED1 14 11 142 -0.124 proportion of matches which concluded with A1 102 1483 121 +0038 a goal gap of at least three: 21.0%. As for the SI1 142 1473 142 -0041 average goal difference, Champions League is ES1 142 142 1.44 0.04 also where the trend towards imbalance is the ER1 14 14 140 -0.00 most apparent between the first and last five E1 177 14 140 0.0 seasons taken into account.