Some teams have the luxury of trotting out a consistent starting lineup week after week. Some do not – usually either as a result of excessive injury concerns or consecutive poor showings.
Over the course of the season, coaches are forced to shuffle and shift their first eleven almost on a weekly basis. For example, only 37 times throughout this season (through July 1) has a team put out the same lineup in consecutive matches – that's roughly 12 percent of the total games played. Of these 37 instances, only Sporting Kansas City have put out a carbon-copy lineup on more than five occasions.
Unsurprisingly, Sporting Kansas City have made the second-fewest lineup changes in MLS this season, closely following the Chicago Fire. On the other end are the LA Galaxy, a team whose form seems to be as inconsistent as their starting lineup.
|Sporting Kansas City||20||1.33|
|New England Revolution||27||1.80|
|New York Red Bulls||27||1.69|
|San Jose Earthquakes||36||2.25|
|Real Salt Lake||41||2.41|
But, does having a consistent starting lineup really matter? Our sample size is relatively low, but there seems to be some evidence that it does.
The average amount of points gained by a team in MLS through July 1 is 1.39. So far, teams that don't make any changes to their starting lineup are averaging 1.65 points per game. While the league-wide average sits well inside the standard deviation of 1.36 points, these findings are fascinating. Earning 0.26 more points per game over a MLS regular-season schedule of 34 games is 8.8 points – nearly three wins.
While it's probably impossible for a team to have a consistent starting 11 over the entire season (and it's probably sub-optimal to play the same players every week, given fatigue concerns), these findings may help us quantify just how valuable a "healthy" team is.
Here are the expected point values for all of the substitution thresholds as well as the number of times each has occurred up to July 1.
As expected, team that make excessive lineup changes earn fewer points, starting to decline at three and sinking rapidly beyond that number. This is intuitive for a handful of reasons. First, teams that are forced to replace their previously "starting" players are likely replacing them with players that are not normally up to the same standard. Second, with a consistent starting squad, players are more comfortable with each other and surely perform as a more cohesive unit.
There is a lot of common sense here, but the responsibility of analysts is to question even the most obvious conventional wisdom. For an outsider, it could have made logical sense that lineups most different than the previous game would perform optimally because fewer players would be tired. As seasoned observers, we know that team synergy is important – but it wasn't something that was easily explained in a statistical sense.
We've taken a step in that direction here. As always, though, this is just a tool – looking at lineup chances surely isn't a perfect way to measure team synergy. But it works as a good enough proxy to prove that it's valuable.
Devin Pleuler is a computer science graduate from Wentworth Institute of Technology in Boston, where he played on the men's varsity team as a goalkeeper. He's certified as a coach through both the USSF and NSCAA, and writes the Central Winger analytics column for MLSsoccer.com.