Does anyone know how it really works? For instance, tonight, Florida State plays Clemson. I realize that if FSU beats Clemson, it helps MU, but how much? Who should we be rooting for in the UConn Syracuse game? What would be more benificial for MU? Just curious.
I don't know if there is an actual way to quantify the benefit of FSU beating Clemson in terms of an actual figure or amount. It really boils down to the higher FSU's RPI is at the END of the season, the better for MU and so any game they win against another high ranked team in the RPI helps.
At this time we need to root for UCONN to win against Syracuse. We need UCONN's RPI to get higher. THey probably aren't a bubble threat to us, considering we beat them head to head. Syracuse's RPI is unlikely to fall much out of the Top 5-7 all year, so a win by them wouldn't really help our cause. UCONN wins, and mayber their RPI jumps into the Top 50..so we get a win against a Top 50 team. Considering we beat UConn head to head, I would have to think we would get a tourney nod over them..if both MU and UConn end up being bubble teams.
For big east games, it's almost always a wash as far as RPI (unless it's an MU game of course...). For pre-conference opponents, we always want them to win every other game that season.
How much does it help, well...I'll leave that to someone with a better calculator than mine.
From (the all-knowing) Wikipedia:
http://en.wikipedia.org/wiki/Ratings_Percentage_Index
The exact formula for determining the RPI of a team at any given time is as follows.
RPI = (WP * .25) + (OWP * .50) + (OOWP * .25)
Where WP is Winning Percentage, OWP is Opponents' Winning Percentage and OOWP is Opponents' Opponents' Winning Percentage.
As mentioned, the WP is weighted based on the locations of the games being played by the team (the other two; OWP and OOWP are not). The exact value of a home win or away loss is .6, whereas the value of an away win or home loss is 1.4. Games played at neutral locations count as 1. When calculating this number, games against subdivision opponents are ignored whether the game is won or lost.
The OWP is calculated in a similar way, ignoring location (every game is worth 1 point) and games against subdivision teams. It does have a few added restrictions, though: first, it ignores the game/games played against the team in question. It also requires that the Opponents being examined have their (unweighted) WP's created before averaging them together.
The OOWP is the most elusive number for most people to calculate, but there are a few tricks for finding it. The OOWP is another way of saying your Opponent's OWP. To reiterate, the team in question is part of the team's OOWP (Opponents' Opponents' Winning Percentage). Ignoring this aspect is one of the most common mistakes made in calculating RPI, for, mathematically, it shouldn't be there, and the most re-occurring opponent of your opponents is yourself. Ignoring the team in question causes a large margin of error. Also, you cannot just average the OWP of your direct opponents, as doing so ignores the fact that every team has played a different number of teams; this would unfairly weight the opponents of teams who have played less.
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Easy enough, right?
Basically, Rocky is correct... BE teams playing other BE teams, it's mostly a wash by the end of the season. For both conference and OOC opponents (not just those you beat, but every one you played), the further their winning percentage (and their opponents') is from your RPI, the more of an impact it will have on your RPI. For conference teams you play twice, that impact will double. Such is why DePaul has the greatest effect on our RPI... not only is their record and opponents' records furthest from MU's RPI, we've played them twice so the effect is doubled.