With the 2013 college baseball season comes a significant change in the RPI formula, which is used as a determining factor (one of many with plenty of controversy in between) in a team's selection to the NCAA tournament.
The revised RPI formula is as follows:
* Each road victory will be valued as 1.3 instead of 1.0
* Each home win will be valued at 0.7 instead of 1.0.
* Neutral-site games will retain the same value of 1.0.
Each home loss will count 1.3 against a team's RPI and each road loss will count 0.7 against a team's RPI. The weighting is based on data showing that home teams win about 62 percent of the time in Division I baseball.
An institution's RPI will still consist of the following three factors:
* Division I winning percentage (25%)
* Opponent's Division I winning percentage (50%)
* Opponents' Opponents' Division I winning percentage (25%)
The RPI changes were first proposed in 2011 in an effort to level the playing field between teams (mostly cold weather schools) who play a disproportionate number of their games on the road and those that do not (I'm looking at you, LSU, playing Tulane at Turchin Stadium isn't really a road game).
The NCAA released a comparison of what the adjusted RPI would look like if it were applied to the 2011 season. Insidepitch.com did a breakdown of the NCAA comparison, finding:
Of the 58 teams who dropped 10+ spots
- Ten were from BCS conferences (at the time)
- States with the most schools that dropped ten or more spots in the RPI were California, Tennessee, North Carolina, South Carolina (all with six), Louisiana and Texas (both with five)
- Tennessee (-32), Duke (-31), Lipscomb (-28), McNeese State (-27), Tulane (-25) and the Citadel (-25) all fell 25 spots or more
Of the 48 teams who gained 10+ spots
- Eight were from BCS conferences (at the time)
- States with the most schools that gained ten or more spots in the RPI were New York (with eight), Illinois and Indiana (four each)
- California (+42), Alcorn State (+41), Central Michigan (+34), South Dakota State (+31), Maine (+31), Purdue (+28), Binghamton (+27), Southern Illinois (+27), Utah (+26), Le Moyne (+26) and Princeton (+25) all jumped 25 spots or more
Obviously there were some significant changes when looking at 2011, but whether or not these would have affected NCAA tournament selection we do not know as the NCAA gave no indication about that.
The big question is, what affect will the new RPI changes have this season?
I asked Boyd Nation of the popular college baseball site Boydsworld.com what he thought of this year's RPI changes. Nation has been releasing his pseudo-RPI's and the ISR (Intended Strength Rating, basically a measure of strength of schedule) since 1998. He intentionally doesn't track the number of visitors because he's not interested in monetizing the site beyond paying for hosting.
The following is the result of a Q&A between myself and Nation:
- Are you in favor of the changes to the RPI formula this season?
The ISR contains an adjustment for home field advantage, so the basic idea is sound. The mechanism is as good as they could do within the confines of the basically broken RPI framework. The big problem is that they severely oversized the adjustment.
- Broken RPI Framework?
The way they use it is reasonably OK; the problem is the system itself. The RPI measures of strength of schedule are based too heavily on winning percentage and give an advantage to teams in areas of the country where there are more D1 teams, since their opponents are less likely to have played each other.
- Is there anything you would have done differently?
The right size for the adjustment, based on historical data, is for road wins to count as 1.1 neutral wins, with home wins correspondingly set at 0.9.
The "right size for the adjustment is 1.1... based on historical data". Could you expound a bit on that?
In conference games (so the scheduling is always home and home) over whatever period of time you want to look at, the home teams wins 54-55% of the time. That corresponds to a 10% advantage ((55-50)/50), which would match up to the 1.1 adjustment.
- Do you feel that the changes will level the playing field between cold and warm weather teams?
No, any effect will be minimal. It's more likely to assist southern mid-major teams, but even there I don't see a big change. The one possible exception to this might come if the southern powers panic and heavily change their scheduling practices, but that's unlikely; the economics argue against it unless they see that the new formula is really hurting them, and that's unlikely to happen.
- Any sort of predictions you'd like to make about how the changes in the RPI will ultimately affect this coming season, specifically, do you think it will result in more cold weather teams being selected for the NCAA tournament?
This year the effect will really be negligible overall, since schedules are set far enough ahead of time that nothing really changed for 2013, given that the actual impact of the RPI changes won't make much difference.
Nation's belief that the RPI changes won't have much of an effect this season runs counter to popular opinion, although most of the comments I've seen express an opinion on whether or not the formula should have been changed, but little analysis (other than the 2011 comparison noted above) on what real effect it will have.
That the RPI change will have an effect is largely based upon the NCAA's reputation of relying heavily on the RPI for NCAA tournament selection. However, last year LSU did not make the tournament despite having a RPI of 25. The Tigers finished ninth in the SEC, but the selection committee chose St. John's instead, leading to speculation that more value was placed on where a team finished with regards to their conference standing than basing selections as heavily on the RPI.
Might the RPI have changed only for it to not have the influence its had in year's past?
In the end, teams will still need to win their games, and given last year's snub of LSU, worry about finishing in a decent position within their conference.
One would hope that RPI changes make a difference and even the playing field a bit for cold-weather teams who have to spend the first two to three weeks of the season traveling. Whether that happens or not, well, perhaps later this season we'll do an analysis on the old RPI versus the new, but even then that may not make much difference.
The difference will come at the end of the season when the NCAA goes through the selection process.