I inserted myself in to this discussion on Wednesday night, and I wanted to clarify a few things as the 140-character limits of Twitter are a VERY poor communication medium on such a complex topic. Here are my somewhat-informed opinions on the topic.
- If the idea of a CCL Curse is that clubs who participate in CCL have never won a playoff series, it's flat out wrong. As recently as 2009 this curse was broken. The Houston Dynamo participated in the 2009-2010 CCL group stages due to the 2008 Supporter's Shield, and promptly eliminated the Seattle Sounders in the first round of those playoffs.
- What is correct is that an overall difference in the number of competitive matches played in a season (MLS, CCL, and US Open Cup) is a statistically significant predictor of the outcome of a two legged playoff. Yes, even with the small sample size (64 clubs over 32 matches) it passes basic statistical tests. The model developed in that March post showed that each additional match a club plays beyond their opponent's total number of matches lowers said team's odds of winning the series by 7.5%.
- Historical data suggests that match differences of more than four mean the club with fewer matches is virtually a lock to get through. The 2009 Dynamo are the lone example of a team bucking that trend - they had played five more games than the Sounders when they won that playoff series. No other club with more than four more games played has made it through the two-legged round.
- The occurrence of a large difference in the number of matches played between playoff opponents certainly has risen in the CCL era (2008+). The number of matches contested by teams with a game differential of four or more has doubled in the CCL era (see end of this blog post for the raw numbers).
- Clearly, the game differential statistic is not deterministic and is bound to change over time, perhaps even this year. As Sarah Rudd at On Football has pointed out, LA, Seattle, and Real Salt Lake are all sporting some of the freshest squads in the playoffs given their superior squad rotation during the competitions throughout the year. Larger MLS roster allocations than in year's past have also helped. A minutes-played rather than a crude games-played metric would be preferable - perhaps it is something I can work on with Sarah this off season. Nonetheless, it's scary that so much of past performance can be boiled down to one crude metric.
- Most importantly, none of this is deterministic. Teams beat the odds all the time, and the odds change with each passing year. MLS constantly tweaks their playoff format and who qualifies for it, and they change the economics of the game as well which is key to squad rotation and having the best shot at multiple competitions. The numbers only tell a story of what's happened in the past, and can only be one of many guides as to how things might operate in the future.
There's a pretty big split in odds between the Eastern Conference and Western Conference squads, mainly due to the huge divergence in the number of games played. Keep in mind that previous analysis has also shown that more experienced coaches actually fair worse than those with less experience when it comes to two-legged ties - this may be due to those same coaches being tied to more successful teams who play more matches, a possibility I will explore this offseason as well.
I don't see any reason to pick against the numbers in the Sporting KC/Colorado Rapids series. Sporting KC has been in great form the second half of the season, and should use that form and rested legs to their advantage against Colorado. In contrast to the LA/NY series, this one has the shortest travel distance for the two participants - 600 miles - which may provided an even bigger advantage to the winner when it comes to weariness in later rounds.
I'm going with the numbers in the Houston/Philadelphia match up and say Philadelphia wins the series. To be honest, I don't have much individual information on either team, having not really watched them all season. Far more observant and intelligent commentators can break this one down for you. In the absence of my own observations, I'm sticking with the data.
The NY/LA match up presents an interesting choice for me. As a biased Sounders supporter, I'd love to see NY take out LA. To be honest, it might make the Sounders road a little easier if they were to make it through their semifinal round - the Sounders have only won a single league match against LA over the three years they have been in the league. Plus, if the Sounders were to make it to the final they would host that match (and maybe I would get that beer I am owed by a certain NYRB supporter...). Both teams come in to this match up a little banged up, but LA clearly has been the more consistent team all year long. They've also done a much better job at rotating players over the season as they've competed in multiple competitions, and will actually come in to this series with a more rested squad than New York. Perhaps the numbers make this a close series, but it's very hard to bet against LA with the season they've had. I'm going with the Galaxy.
The final match up - Seattle/Real Salt Lake - is a bit tougher to pick. Beyond my own bias, I also have watched nearly every Sounders match this season and have a good idea as to what makes them tick. The spark plug in their offense - Mauro Rosales - is out for the first game and will likely only play a minimal role in the second game if he's even fit for it. Without Rosales, the Sounders can look flat at times. They'll also be coming in to this series with a heavy playoff history on their shoulders - one goal and no wins in four playoff matches. For all their success, they've largely fallen flat in the playoffs. It will be interesting to see if Sigi Schmid puts Sammy Ochoa in the starting lineup given his solid performances and several goals scored the last few matches. The real question will be whether Seattle can produce enough offense without Rosales to win the series, and then get him back for the Conference Finals. As is the case in the NY/LA match up, the match count is a bit deceiving in this one. Seattle has done a good job at squad rotation as well, and thus comes in with a slight advantage versus Real Salt Lake (although it's much smaller than LA's advantage vs. NY).
I also think Real Salt Lake is a bit of a dangerous team. They're playing with a chip on their shoulder, looking to continue to prove 2009's MLS Cup and this year's run to the CCL championship match weren't flukes. This series may just be the best to watch out of the four. I'll be at the second leg, and I narrowly believe I'll be watching the Sounders win their first playoff series in their three year existence. If I'm right about this series, and LA wins their series, we may just see the whole match differential metric become statistically insignificant and finally stop talking about the "CCL Curse".
I'll check back in a week from now with odds on the Conference Final match ups. Enjoy the semifinal round!