It’s Beanpot Tuesday! Yay!
But Boston College isn’t playing for the title! Boo!
Harvard and Boston University both pulled upsets in the Beanpot semifinals, sending Northeastern and Boston College to the consolation game at 5pm. As disappointing as that is for both BC and NU, both games on Tuesday have huge Pairwise implications for the three ranked teams involved — BC and BU in particular.
Let’s take a look at what the Pairwise looks like today.
Unless there are some upsets in the conference tournaments, the top 7 in the Pairwise will make it to the NCAA tournament (the eighth and final spot will be filled with the CHA champion, whose highest ranked team, Robert Morris, is ranked 16th). That means that if the season were to end today, Boston College would be in and Boston University would be out.
But the Pairwise is much more volatile than it looks. BC and BU have been dancing on a tightrope the last few weeks because of how the Pairwise is constructed. Normally the Pairwise just follows RPI and that’s the end of it. But the Pairwise consists of three pieces: RPI, head to head (H2H), and record against common opponents (CoOpp). Everything is worth one point, except H2H is worth one point for each win. Comparison ties are broken by RPI, so if two teams don’t face each other H2H, then the team leading in RPI gets the comparison even if they lose CoOpp, because RPI breaks that 1-1 tie.
With that crash course, let’s look at the BC/BU comparison and see just why the Beanpot is going to be such a big deal.
BC wins the comparison as it stands today, and holds RPI — so you’d think BC is in good shape. But if the Terriers can flip the CoOpp point (as they have done on and off the last few weeks), they’ll claim the comparison point and flip into a tournament spot.
CoOpp is calculated by adding up the winning percentages against each shared team.
So, BC’s 6.167 comes from:
3-0 vs. UConn (1.000)
3-0 vs. Holy Cross (1.000)
1-0 vs. Maine (1.000) [two games left to play]
2-1 vs. Merrimack (0.667)
1-1 vs. New Hampshire (0.500) [one game left to play]
1-2 vs. Northeastern (0.333) [one game left to play — Beanpot]
2-1 vs. Providence (0.667)
3-0 vs. Vermont (1.000)
...which adds to 6.167.
BU’s 5.833 comes from:
1-0-1 vs. UConn (0.750) [one game left to play]
3-0 vs. Holy Cross (1.000)
1-2 vs. Maine (0.333)
1-0-2 vs. Merrimack (0.667)
1-0 vs. New Hampshire (1.000) [two games left to play]
0-2-2 vs. Northeastern (0.250)
2-0 vs. Providence (1.000) [one game left to play]
2-0-1 vs. Vermont (0.833)
...which adds to 5.833.
Simple enough! That’s a difference of 0.333 between the two teams. That’s not all that small, and you can see that BU can only really improve their CoOpp record by winning their last game with UConn, which would only bump them up by 0.083.
But stop the music! We’re forgetting one big factor: BC just played Harvard, and BU will be playing Harvard tonight. That will introduce another common opponent, and one that will have a disproportionately large effect on the comparison.
BC lost its game against Harvard, so BC’s record won’t change — they’ll be adding a 0.000 winning percentage. But if the Terriers beat Harvard in the Beanpot final, they’ll be 1-0, adding a massive 1.000 to their total. That would make for a nearly insurmountable difference of 0.667 for the Eagles to overcome — it would require at least two BU losses the rest of the way (not impossible, but the Terriers only have four games left after the Beanpot) along with BC winning every one of their own games after the Beanpot.
BC’s only saving grace in this scenario would be that a win over BU in the Hockey East tournament to erase the Terriers’ H2H advantage would make the whole comparison revert back to RPI and get rid of the CoOpp point entirely.
Let’s take a look at just how big these two games are for the Eagles and Terriers based on how the Pairwise would be affected by the results. First, let’s see what would happen if BU beats Harvard, and the Eagles lose to Northeastern — the worst case scenario for BC, and the best for BU:
As expected, BU jumps ahead despite being behind in RPI.
Now let’s look at the opposite — BC’s best case scenarios, beating the Huskies and BU losing to the Crimson:
This would be crushing to BU, as they would no longer control their own destiny for an at-large tournament position. BC, on the other hand, would solidify their spot in the top seven and pretty much be in the driver’s seat from here if they can manage to not stumble the rest of the way.
It’s probably not the best feeling for the Eagles to have the evening’s other game have such a disproportionate effect on their Pairwise prospects... but this could have been avoided in the first place if they had just beat the Crimson last week. Such is the 2018-2019 NCAA women’s hockey season.