Saturday, June 29, 2019

Teams With 9 Points in the Group Stage Don't Usually Win International Soccer Tournaments

Colombia flaming out of this year's Copa America in their first knockout game poses the question - how often do teams that compile 9 points in the group stage go on to win international soccer tournaments?

In last year's Men's World Cup, for example, 3 teams came out of the group stage with 3 wins: Uruguay, Croatia, and Belgium. None of them won the title. In fact, the last team to go 3-0 and then win the whole thing in either the Men's OR Women's World Cup was Germany in 2003.

To compile a larger dataset, I looked at the last 4 instances of 4 major international tournaments: Men's World Cup, Women's World Cup, Copa America (South America), and Euro Cup (Europe). To back up this choice: every single Men's World Cup - ever - has been won by Europe or South America (no one else has even made the final).

PointsCountSemis?Final?Win?Semi %Final %Win %1st2nd3rd
Note: 8 points is mathematically impossible in the 3 points for win/1 point for draw format

Aside from the handful of teams that have advanced with 3 points (only remotely possible in a format where 3rd place teams can advance), teams coming out of the group stage with 9 points have been more likely to make the semifinals and the final - but strangely have underperformed in that final game. The only 2 teams to do it in the time period I looked at were Germany in the 2003 Women's World Cup and Spain in the 2008 Euro Cup.

This oddity does not seem to hold up when I look at results by finish in the group stage:

FinishCountSemis?Final?Win?Semi %Final %Win %

So why do teams that win all 3 games not win the tournament? You would imagine the teams that sweep the group stage are naturally better, and thus should advance further, even when you disregard any notion of momentum. Are they tiring themselves out? Or is it just fluky performance over the 28 teams (16%) to accomplish this out of the 176 in my dataset who advanced to the knockout stage?

This question is definitely pertinent for the current Women's World Cup semifinal group, as England, United States, and Netherlands all meet this criteria.

Thursday, June 20, 2019

Competitive Balance in MLB, NBA, NFL, and NHL

In light of the end of this year's NBA and NHL postseasons, both Finals in each sport had a team that seems to be there almost every year (Golden State in NBA and Boston in NHL). Which begs the question: are both sports devoid of competitive balance (CB)? Especially in relation to the other 2 major pro sports leagues in North America, MLB and NFL?

I've measured CB before in NCAAB and the NBA, but haven't compared the leagues against eachother. So I've compiled all semifinalists over the past 10 years in each league, and calculated the Herfindahl–Hirschman Index (HHI), which measures CB. In this case, it is the sum of the squares of the number of semifinal (conference championship) appearances by team i (f_i) during the designated period, over the number of possible semifinalists during the period. To account for the fact that there are 4 teams that are semifinalists each year, we include a multiplier of 4 in the summation.

The closer HHI is to 1, the less CB there is in the league. Complete CB (4 different teams every single year) would be 0.1.

League# of Dif TeamsHHI

NHL has the most competitive balance over the last decade! At least in the conference finals. NBA and NFL are actually both tied for the least amount of CB. The NFL is very much weighed down by the Patriots, who have made 8 of the last 10 conference title games.

What if we just look at the final round of each league? 

League# of Dif TeamsHHI

NHL and MLB are tied, and unsurprisingly, the NBA is by FAR the least balanced (Warriors/Cavs/Heat/Spurs account for 75% (!!!) of the Finals appearances over the last 10 years). Similarly, the Patriots account for half of the Super Bowl appearances over the last decade.

This raises another question: is there any correlation in CB and the salary cap structure of each league? NFL and NHL are hard caps (you literally can't go over the cap), and that appears to exhibit mixed results (primarily due to the Patriots). MLB and NBA have soft caps (you can go over the cap, but you get penalized via escalating taxes for doing so), but MLB has a much softer cap than NBA (less severe penalties). So the CB between the two appears to be more influenced by the structure of their respective playoff rounds and the games themselves (baseball has shorter series and more volatility game-to-game).