Below find an article about the various RPIs in play. FYI, from Wikipedia: RPI = rating percentage index. It is “a quantity used to rank sports teams based upon a team's wins and losses and its strength of schedule. It is one of the sports rating systems by which NCAA basketball, baseball, softball, hockey, soccer, lacrosse, and volleyball teams are ranked.”
This article is from the Northwest Conference website by their basketball news blogger, Ted House. I’ve edited a bit in italics to add some more dimension.
Dec 2, 2018 10:41 a.m.
1st Order of Business: RPI 301
In the Gym
By Ted House, Professor of Research, THE RPI School
When I’m out and about, I get a lot of questions about this RPI business. And that’s fine. Keep them coming, because somehow, it’s fun to talk about. However, when I get in these conversations, sometimes I get the idea that we aren’t discussing the same RPI. There are multiple RPI’s, so come clean on the differences.
This is the third school year for the District 1 & 2 RPI for the 2A classification. It is used for football, volleyball and girls soccer in the fall; boys and girls basketball in the winter; and softball, boys soccer and baseball in the spring. With slight scoring differences for football and soccer, the RPI creates standings for the 13 2A teams in District 1 & 2, and seeds them into their (sport) specific district tournaments.
In District 1/2, 2A teams are members of three different conferences, the Northwest Conference, Wesco Conference, and KingCo Conference. Each conference has members from different classifications, and the RPI system is used as a way to seed teams fairly for the post season (as qualifying 2A teams from each conference meet in the District 1/2 tournament). The Cascade Conference disbanded after the 2017-18 school year, and its two remaining 2A teams, Cedarcrest and Archbishop Murphy, have joined the Wesco 3A Conference. (And Ted doesn’t say this, but Cedarcrest and ABM are joining Mountlake Terrace which is already a 2A school in Wesco. Shorecrest was also a 2A school in Wesco in recent years, though they are 3A now. ) Liberty and Sammamish are 2A teams that compete in the KingCo 3A Conference in District 2.
With the addition of the two (more) 2A schools to the Wesco 3A, and with Ferndale and Squalicum competing in the Northwest Conference (except for football), the 3A schools in District 1 have adopted the same RPI system that has been used by the 2A classification. As of this school year, Ferndale and Squalicum will be included in the RPI system with the 12 3A schools in the Wesco. This will make the run-up to the 3A post season much easier to follow.
On the state level, the WIAA is still only using an RPI system for basketball. It is completely different measurement than the local 2A and 3A district RPI. (And Ted doesn’t say this, but besides using a different formula, it is used for a different purpose – seeding teams into the regional round of the state tournament. First, a team must win its way through its district tournament and be one of the teams qualifying for regionals. For example, in 2A basketball in District 1/2, the teams are seeded into the district tournament according to the local RPI. Then, the top four teams coming out of the District 1/2 tournament qualify for the regional round of the state tournament. No matter their state qualifying placing in the District 1/2 tournament (that is, first, second, third or fourth), they will be seeded into the regional round according to their state RPI. So this is why any team’s state RPI matters not much at all unless they qualify for the regional round of the state tournament by placing in their district tournament.)
The state basketball RPI counts all games played, through district tournaments. This means league, non-league, and all post-season games at the district tournament level. The (state) RPI equation includes the team’s winning percentage (worth 40%); its opponents’ winning percentage (40%); and its opponents’ opponents’ winning percentage (20%).
For its first two years (in the state RPI), a “25/50/25” percent system was used. This year, those numbers have changed to 40/40/20. This will give more weight to a team’s own winning percentage, and slightly less to the other two factors (than they were given in previous years).
Games against touring Australian teams (or any international team) are not counted in the state basketball RPI. Furthermore, if a team has “out of state” opponents on the schedule, they must keep track of those teams’ records throughout the season. However, they do not have to track the opponents’ records of that team (that is, the opponents’ opponents’ records).
For example, if Zillah plays Oceanside, California, then Zillah must keep track of Oceanside’s record because they are their opponent. (And presumably they convey this to the state RPI makers somehow.) But the opponents of Oceanside (the final 20% of the (state’s RPI) equation), will default to a .500 record.
On the other hand, the RPI used by our local 2A and 3A teams (District 1/2) only counts the league games that are on the schedule. (Emphasis added.) (And) teams can only gain points for wins. (And) a team will get more points for beating a 3A team, as opposed to a 2A or 1A team, which are in proportion. (I don’t know what he means by “in proportion.” But Cedarcrest and Murphy are in a different situation than previously when they were in the Cascade Conference which was a league with only 2A and 1A competition. Wins against 2A and 1A teams count less than wins over 3A teams. And only league wins count. I’m not sure if that will matter, but now that CHS and ABM are in Wesco, they do not have league games – thus possible league wins, though at a lesser value -- against 1A teams at all.) There is also a bonus if a team you beat finishes with a record of .500 or higher. It’s the final league record that is most important. (Or rather, it is the one that counts in the end.) You may beat a team in the second week of the season that was over .500 at the time. But if that team finishes the league schedule with a record that has fallen under .500, that win will be worth less. (So basically, it’s a moving target throughout the season.)
Another new RPI example is the SPSL (South Puget Sound League) 2A which has 16 teams that are split into three divisions. They have adopted an RPI system this year to seed teams into their district tournament as well. However, the SPSL 2A has chosen to use an RPI system that is similar to the WIAA’s state basketball version, where they will count all games played in the regular season, along with the three percentages.
You can find a district RPI link on the home page of the individual sport. (This is for either the Northwest Conference or the Wesco Conference website.) It says, “RPI” near the upper left, in the row between standing s and photos. For basketball season, the district RPI will begin its updates in January, after enough games have been played to make it realistic.
I realized this is convoluted! Hopefully, less now than a few minutes ago. Just remember that there is a state basketball RPI for everyone. And there are district RPI’s for 3A teams in District 1 and 2A teams in Districts 1 and 2. I’m just doing my part to keep District 1 as the most informed district in the state!
(Okay, me again. And there is another ranking out there, just to add to the confusion. On the MaxPreps page, there is a "ranking" tab. Cedarcrest's rankings on MaxPreps. It shows the team's ranking in 2A, its (theoretical) ranking in the entire state regardless of classification, and a (very theoretical) national ranking. When I've looked, the MaxPreps 2A ranking does not match the WIAA 2A ranking for Cedarcrest (even though the WIAA RPI supposedly uses the scores from MaxPreps to generate their RPI).
Link to Ted House's article
Link to District 1/2 RPI on Wesco website
Link to WIAA state RPI for each classification and FAQs