Saturday, October 17, 2015

MLS Shootout (part 2) - One Table to Rule Them All

The MLS shootout was introduced in 1996 to prevent American sports fans from suffering through a tied soccer game.  The assumption was that we would prefer an NHL hockey-style shootout to a game without a winner and that we wouldn't mind becoming the laughing stock of the rest of the soccer world.

Assuming a competitively balanced league where any team has an equal probability of winning, losing, or tying any game, I showed in the last post that teams have less incentive to fight for a win in a late tied game now that there is no shootout.  That is, teams are more likely to settle for a tie now that it guarantees a point.  However, when looking at the percent of tied games each season, it became clear that the jump in the percent of tied games didn't occur immediately after the shootout era, which ended after the 1999 season (see the reproduced graph below).  If we take a closer look at the data, we can see that the percent of games ending in a tie has more to do with conferences and the rules of playoff entry than shootouts.


The reason for this is simple: since the top teams in each conference gain entry to the post-season, teams are less averse to sharing points when playing non-conference opponents.  For example, when Columbus Crew SC tied the Vancouver Whitecaps this past April, the Crew didn't mind sharing points with a Western team. The point given away to Vancouver had no bearing on the Crew's playoff chances since Vancouver competes for spots in the Western Conference.  However, the 3-3 draw Columbus had with Toronto was less beneficial as it gave away a point to Toronto, which remained 3 points behind Columbus in the Eastern standings.  So on net, Columbus gained no ground on Toronto whereas the tie against Vancouver gained Columbus a point against all Eastern teams.

It stands to reason then that seasons with more inter-conference games should have less ties as teams fight harder to net 3 points (3 to them - 0 to opponent = 3 net points) instead of 0 (1 to them - 1 to opponent = 0 net points) against conference opponents.  This has already been shown to be the case in NHL by Shmanske and Lowenthal (2007).  But what about MLS?

Taking a look at the percent of tied games plotted against the percent of games played between opponents of the same conference for all non-shootout seasons, it seems that this is indeed the case.  There is a clear downward trend indicating that the greater the percent of inter-conference games, the less the percent of tied games there will be.



Use the data and R script to reproduce this graph and all others below.

What is up with those outlier years with 100% of games being between same-conference teams you ask?  Although MLS actually had 3 "conferences" (East, Central, and West) for the 2000-2001 seasons, entry into the playoffs was granted to the top two-thirds of all teams regardless of conference.   This was also true in 2002 although the league reverted back to 2 conferences (East and West).  So in practice the conferences only served as lists of teams that were geographically close and played each other more often.  This is why I'm treating those years as if 100% of the games played were inter-conference; for the sake of playoffs, they were.  

You have to appreciate the irony here.  In the year where MLS seemed to rebel once more against European football and create 4 team-conferences a la the NFL, what it really had was a single table with an unbalanced schedule.  Single-table purists should add this fact to their arguments; a single table should decrease the number of tied games in MLS.

Back to the shootout era.  Adding these years to the plot, we see that outside of that crazy 1999 outlier season, the pattern still holds.  Additionally, we see the effect the shootout had on tied games independent of conference effects.  Again, outside of 1999, the shootout seasons saw a lower percentage of ties compared to other seasons with the same percent of inter-conference games.


So what can MLS do to minimize the amount of tied games we see? There are two changes it could implement: a single table for playoffs and/or reintroduce the shootout.  Although the latter would explicitly eliminate ties as well as reduce the number of games that ended regulation in a tie, I don't actually want to return to the shootout days. Neither does MLS and neither do you.  But a single table?  When asked about the possibility of a single table back in 2010, Don Garber replied

...every year we do deeply analyze whether or not it makes sense for us to have a single table and no playoffs. We also evaluate whether it makes sense to have a single table and playoffs, or whether it makes sense to have conferences and playoffs.

...We're going to change it if we believe we could have a more compelling format and one that might be perhaps more balanced. ...It should be a format where there is more media coverage, more television ratings and more attendance as we get down to an event that is a single, stand-alone event, our championship game, the MLS Cup.

...All of those can happen within a single table format. The single table discussion is whether there is a single table or whether there are conferences?
I have no idea what goes on when the top brass of MLS meet to deeply analyze using a single table.  What I do know now is that the evidence above strongly suggests that doing so would reduce the number of ties.  It would also appease the Eurosnobs out there who use words like "cappo" and refer to games as "matches" and fields as "pitches" and....ok I'm getting nauseous, enough.

And if a single table is not in the works, we could  theoretically baby-step our way to one by returning to the days when last playoff positions were given to the best teams regardless of conference (2007-2011).  For example, in 2008 the top 3 teams in each conference were granted access to the playoffs along with the remaining top 2 teams regardless of conference.  Although this yielded a strange situation where a team from New Jersey, the "New York" Red Bulls (NYRB), entered the playoff bracket in the West and was crowned the Western Conference Champions, it should have provided incentive for NYRB to give more effort against Western Conference teams during the regular season since they were competing for that last playoff spot with Western Conference teams.

2008 MLS Standings

Eastern ConferenceWestern Conference
team
points
team
points
Columbus Crew57Houston Dynamo51
Chicago Fire46Chivas USA43
New England Revolution43Real Salt Lake40
Sporting Kansas City42Colorado Rapids38
New York Red Bulls39FC Dallas36
D.C. United37San Jose Earthquakes33
Toronto FC35LA Galaxy33
                                                               *teams in bold admitted to playoffs

Both Sporting Kansas City and NYRB  had to earn more points than the 4 lowest ranked teams in the Western Conference to make the playoffs in 2008.  Thus, their intra-conference games should have been given the same importance as their inter-conference games.  The same should be true for all teams ranked around the last playoff spots and we should see more teams push for wins in closely fought games.  Although this incentive should exist in theory, it's not blatantly obvious at first glance.

The years for which some teams are ranked on a single table to gain entry into the playoffs are represented by blue circles.  The areas of the circles represent the proportion of teams that will make it to the playoffs via a single table comparison.  The absolute number has been as few as 2 teams and as many as 10 teams.  If the single table comparison caused more teams to push for wins in late tied games, we would see less ties when the circles are bigger and the circle years should be below the dots representing no single table comparisons.  Unfortunately, the years that used a single table for some teams are not close to many comparison years in the plot for us to draw a conclusion.

Moving forward, I think things are complex enough that it's time to carry out a logistic regression on game level data so that we can simultaneously control for all the moving parts influencing tied games in MLS.  These include but are not limited to, overtime structure, conference structure, playoff structure, and of course competitive balance within the league.  Maybe then we can find out just what was going on in that 1999 season.

This project started out in my mind as a simple investigation of the incentive effects of the MLS shootout, a rare gem in soccer history.  Upon diving into the data, it has become so much more.  That is how research usually goes.  And for all of my projects, you can replace the word "usually" with "always".  But this is why you should choose topics you love.  Then you don't mind so much when it takes 10 times as long as you thought it would.








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