RPI for 2008

I had a gentleman sitting near me mention the RPI last weekend, I actually felt relatively competent in the workings of the RPI to explain a little of how it works with him.Indeed Shadrach, UPSF is doing many more Pilot fans than just those of us here a favor by proxy.

Purplegeezer wrote:
There were all sorts of accusations of politics. There was even the suggestion in a Eugene paper that Buzz Stroud, as chair of the West region, engineered the selections so we wouldn't have to face them.

I don't think they thought that through. The choice was face an unranked team team we beat 3-0 at in Eugene at home or go on the road at high altitude against dangerous #14 BYU and #10 Utah.... If Buzz engineered that he should have been fired.

Yeah, because we want to travel every year. If anything Buzz should have tried to get the Ducks in.

(Assuming anyone from UP has any pull with the committee.)

Come on Duck fans--it's not always about you.

The various NCAA sports committees have rules about when a person connected to a team involved in a decision can participate and when they can't. I'll see if I can find them somewhere. They make it very hard for a committee member to lobby for his or her team. Of course, maybe they can lobby another member in private before hand?

Just a quick note for today. I'll run the numbers with this weekend's games tomorrow and post them then.

The Pilots' non-conference opponents had another good weekend, with cumulative results of 12-4-2. The Pilots' two conference opponents were a combined 13-14-4 against teams other than the Pilots. Both sets of numbers will figure into the Pilots' strength of schedule. Our non-conference opponents are really helping us, so far. Let's hope they keep it up.

Of course, the most important thing is for the Pilots to keep winning.

The Pilots are 15-1-0 with a 14 match winning streak and 2 matches to go in the regular season.

The table is almost set for the 2008 Pilots to make their final charge of the year!

I've posted a new RPI report covering games through October 26 on the BigSoccer website. The Report is in two pdf files and covers teams ranked 1-119. For those who want and are able to download the files, you can find them using the following link: http://www.bigsoccer.com/forum/showthread.php?p=16104855#post16104855

The files are attached to the cpthomas post dated October 27, at 2:09 pm.

For those who aren't able to download the files, here are the RPIs for the top 100 teams. You'll notice that Portland has moved from third to fourth, having been bypassed by UCLA.

1 North Carolina U 0.724287
2 Stanford 0.718698
3 UCLA 0.708170
4 Portland U 0.705206
5 Florida State 0.698767
6 Notre Dame 0.695734
7 Florida U 0.676763
8 Boston College 0.673799
9 Texas A&M 0.665943
10 Duke 0.660700
11 Penn State 0.659014
12 Oklahoma State 0.656099
13 Virginia U 0.650948
14 Texas U 0.649779
15 Colorado U 0.638682
16 Washington U 0.638059
17 USC 0.637132
18 BYU 0.628524
19 Wisconsin Milwaukee 0.614916
20 UCF 0.614593
21 Wake Forest 0.613759
22 Rutgers 0.611922
23 San Diego U 0.611826
24 Miami FL 0.610956
25 Princeton 0.609464
26 Long Beach State 0.609276
27 Minnesota U 0.608974
28 James Madison 0.607799
29 Virginia Tech 0.603909
30 South Carolina U 0.603546
31 West Virginia U 0.602478
32 Michigan State 0.602015
33 Arizona State 0.600055
34 California U 0.598641
35 Illinois U 0.598082
36 Auburn 0.595563
37 Charlotte 0.595091
38 LSU 0.594804
39 Kansas U 0.594623
40 Harvard 0.593057
41 Georgia U 0.593055
42 Washington State 0.593003
43 Missouri U 0.592936
44 East Carolina 0.592528
45 Purdue 0.588541
46 Loyola Marymount 0.588139
47 William and Mary 0.587762
48 UNC Greensboro 0.586241
49 Hofstra 0.585656
50 TCU 0.585604
51 Denver 0.585410
52 Arizona U 0.585140
53 Old Dominion 0.582548
54 Marquette 0.580384
55 Georgetown 0.577552
56 Colorado College 0.577204
57 Dayton 0.573468
58 Rice 0.573400
59 Columbia 0.573067
60 Boston U 0.572509
61 Northwestern U 0.571942
62 Utah U 0.571250
63 Oregon U 0.571030
64 Western Kentucky 0.570643
65 Louisville 0.569728
66 UC Santa Barbara 0.569153
67 Memphis 0.569123
68 UNC Wilmington 0.568242
69 Ohio State 0.566024
70 Saint Louis 0.564957
71 St Johns 0.561548
72 Connecticut U 0.559441
73 UNLV 0.558074
74 Davidson 0.555261
75 Nebraska U 0.554848
76 Fairfield 0.554785
77 New Mexico U 0.554026
78 Vanderbilt 0.553213
79 Toledo 0.551046
80 Pennsylvania U 0.549530
81 Long Island 0.548782
82 Villanova 0.548436
83 Fordham 0.546913
84 Tennessee U 0.546212
85 Santa Clara 0.545481
86 Wisconsin U 0.544811
87 Yale 0.543662
88 Belmont 0.542493
89 McNeese State 0.541599
90 Kennesaw State 0.540626
91 Brown 0.538679
92 Dartmouth 0.537956
93 Western Carolina 0.537902
94 Cincinnati 0.537560
95 UC Irvine 0.537186
96 Alabama U 0.536857
97 Samford 0.535909
98 North Texas 0.535025
99 Evansville 0.532623
100 Cal Poly 0.532576

UPSF, Stanford and UCLA play next weekend. It is certain that there will be a win loss or perhaps a tie. In that scenario will one loss or tie move them out of the top four.

Its hard to believe that Notre Dame with no losses will not get a number one seed.

If Notre Dame wins out, you're probably right about them especially since they beat North Carolina @ North Carolina. They've got an interesting problem. Since they're undefeated and untied, Element 1 of their RPI has been and is 1.0000, and that's where it will stay as long as they keep winning. The Big East is not particularly strong, with lower average RPIs than the Pac 10, ACC, Big 12, WCC, Big 10, and SEC (which I've listed in the order of their average RPIs). What this means is that virtually every week, Notre Dame's strength of schedule is dragging down its RPI in relation to the top teams from those conferences. Thus this week, it won two games but dropped a position from 5th to 6th.

Regarding UCLA and Stanford, you're right that there will be either a win-loss or a tie-tie in their game this upcoming weekend, which will have a negative effect on one or both Element 1s. On the other hand, each team will be adding the other team's record to its strength of schedule Element 2. We'll have to see how those two factors balance out. Plus, Stanford also must play USC and will get to add USC's record to its strength of schedule Element 2. Plus, Cal also will be playing the LA schools.

The Pilots need to just keep doing what they're doing, winning one game at a time. That's the part they control. We'll just have to see on the rest.

As long as we are asking you to make the spreadsheet sing, how are UW's and WSU's chances of making the tournament?

I mean, sure they'll get in if they win out, but what if they lose 1 game? If they lose 2?

Unless I am mistaken, OSU defeated WSU this weekend.

upsailor wrote:Unless I am mistTaken, OSU defeated WSU this weekend.

Yeah, UW is at 16 in the RPI. WSU is 42. Last year, 47 got you in. So I want to know if they will make the cut.

Geezaldinho wrote:As long as we are asking you to make the spreadsheet sing, how are UW's and WSU's chances of making the tournament?

I mean, sure they'll get in if they win out, but what if they lose 1 game? If they lose 2?

This is a really tough question. If I'd done this for a couple more years, I might be able to give you a reasonably reliable best guess answer. But I haven't, so here are some things to think about.

WSU and UW play each other plus Arizona and Arizona State. The two Arizonas' winning percentages and their opponents' winning percentages, which will go into Elements 2 and 3 of the two Washingtons' RPIs, are as follows as of today:

Arizona: .5000 and .6239
Arizona State: .5625 and .6231

The two Washingtons' three RPI Elements are:

WSU: Element 1: .5882; Element 2: .6009; and Element 3 .5417
UW: Element 1: .7059; Element :.6316; and Element 3: .5559

So, out of the three games, WSU and UW will each will add three games worth of numbers to its RPI as follows (subject to adjustment based on how all three teams end up through the end of the season):

WSU: Element 1: depends on outcomes of games; Element 2: include average of .5895; and Element 3: include average of .6262.

UW: Element 1: depends on outcomes of games; Element 2: include average of .5502; and Element 3: include average of .6160.

To add further information, right now the average Element 1s of the teams ranked 35-47 in the RPI are .6511; Element 2s are .5701; and Element 3s are .5521.

Based on this, if we assume that the other teams ranked 35-47 will have an end-of-season strength of schedule equal to what they've had so far (in other words, their opponents from here on out will be the same as the opponents they have played so far, which is perhaps a little optimistic), then the strengths of schedule "additions" of WSU, UW, and the "average" 35-47 team will be as follows:

WSU: .6017
UW: .5721
Others: .5641

(WSU does better than UW because UW's record that gets added to WSU's strength of schedule is better than WSU's record that gets added to UW's strength of schedule.)

These numbers aren't exactly right for a number of reasons, but they are the best I can do for purposes of thinking this through. What this means is that both WSU and UW can afford to lose some points from Element 1 -- their own records -- since they look likely to gain points from Elements 2 and 3 -- their strengths of schedule. Since UW currently has a higher RPI, it can afford to lose more points from Element 1 than can WSU.

That's the only real analysis I can do.

As a sheer guess, I'll say that if both teams beat both Arizonas, then they'll both be in. Beyond that, I'd hate to hazard a guess.

Just to totally bore you, I'm going to include here a post I put on the BigSoccer website that further discusses the RPI's discriminatory effect against teams from strong regions and how that effect is exacerbated by the RPI bonus/penalty awards. (I can use words like "exacerbated" because this is such a literate website. ) Here is the post:

I'm going to take a crack at describing how the RPI's difficulty rating teams from the different regions in a single rating system is made worse by the bonus/penalty system. I'll also include a couple of other issues with the bonus/penalty system.

First, some more background on the problem rating regions in a single system.

I've run again a set of average RPIs by region, based only on inter-regional games, covering games through October 26. Those numbers are as follows:

Central .4782
Great Lakes .4826
Mid Atlantic .4798
Northeast .4775
Southeast .4844
West .5387

This week, however, I also ran a set of average RPIs by region, based only on intra-regional games. Those numbers are as follows:

Central .4992
Great Lakes .5005
Mid Atlantic .5041
Northeast .5072
Southeast .5015
West .5006

These last numbers are what one would expect. Each region, using only intra-regional games, is completely separate from each other region. When computing RPIs for completely separate pools of teams, one would expect the average RPI for each pool to be roughly .5000 (with slight variations, I believe, because the different teams play different numbers of games). Assuming each pool has a typical bell curve distribution of teams' RPIs, the RPI distributions also should be the same from one pool to the next. Therefore, if you then bunch all the regions' RPIs together, in any ranking group you choose, you will get the number of teams from each region that is proportional to the number of teams in the region. So, if you are looking at the top 50 teams (which is a good number for tournament at large selection purposes), you would expect to see 18% from Central, 19% from Great Lakes, 15% from Mid Atlantic, 13% from Northeast, 19% from Southeast, and 16% from West, with the percentages based on the percent of teams from that region out of all 318 teams.

So far this season, teams have played 2684 games. Of those, 1726 have been intra-regional and 958 have been inter-regional. In other words, 64% have been intra-regional and 36% have been inter-regional. As a matter of interest, breaking these percentages down by region, the numbers of intra- and inter-regional games by region are:

Central 65/35
Great Lakes 70/30
Mid Atlantic 50/50
Northeast 57/43
Southeast 63/37
West 78/22

(Geographic issues presumably are the reasons for the differences.) What these numbers appear to verify is that the regions (with the except of the uniquely located Mid Atlantic region) in fact do predominantly play within regional playing pools.

Regarding the intra-regional average RPIs, since the pools of teams are completely separate, the average RPIs really provide no basis whatsoever for making cross-regional comparisons of teams. So far as a neutral reader of the RPIs is concerned, the regional pools could be equal or they could be unequal. For example, one pool could be U12s, another U14s, another U15s, etc. Each pool would produce the same cross-section of RPIs.

What this means is that the only basis for comparing the pools to each other is the inter-regional average RPIs. If one is really going to go down the RPI road, the implication is that one first should identify the playing pools' strengths through the inter-regional RPIs. One then should adjust the intra-regional RPIs of teams so that the intra-regional average RPIs of teams from a region are reflective of that region's inter-regional average RPIs. And only then should one combine all into a single system. This, of course, would represent a radical change in the RPI. But the theory, at least to me, seems correct.

The RPI, however, does not do this. Instead, it treats the intra-regional average RPIs as being comparable across regions independently of the inter-regional RPIs. Put differently, although the inter-regional average RPIs suggest that the regions are not of equal strength, the roughly 2/3 of all game data represented by intra-regional games state that the regions are of equal strength.

It's based on this analysis, as well as an experiment I ran with last year's data after the season was over, that I have concluded that the RPI discriminates against teams from strong regions.

Now for how this relates to the bonus/penalty awards. I'll discuss the bonuses, since they are most pertinent to at large selection and seeding decisions. The same reasoning applies to the penalties. There are two sets of bonuses. One set applies to wins and ties in games against teams ranked 1-40 in the unadjusted RPI. The second, lower, set applies to wins and ties in games against teams 41-80. If I am correct that the RPI discriminates against teams from strong regions, then a strong region will have teams that should be in the top 1-40 and 41-80 that are not there; and conversely weak regions will have teams there that should not be there. Since teams play predominantly within their regions, this means that teams from strong regions have a lesser chance to achieve bonus points than they should have; and teams from weak regions have a greater chance than they should have. Thus not only does the unadjusted RPI discriminate, but the bonus/penalty system increases the discrimination.

Just a couple of other notes about the bonus system and I'm done. One of the things I follow is which teams are hovering around unadjusted RPI positions 40 and 80. This is because a win/tie over a #40 teams gives a maximum bonus, whereas a win/tie over a #41 team gives a lesser bonus; and the difference between #80 and #81 is between a bonus and no bonus. I've calculated, based on last year's data and the RPI's accuracy in predicting results of the NCAA tournament, that the RPI's standard error is in the range of .0200 to .0300. In fact, last year, where the RPI differences between two opponents were less than .0600, the RPI was correct in predicting tournament game outcomes only 58.6% of the time. For the bonus awards, the teams around #41 and #80 are much, much closer than that together. So, from a statistical perspective, the bonus/penalty system seems very hard to justify.

Of course, the Women's Soccer Committee doesn't pay attention to the RPI's lack of precision, except to the extent that head-to-head results and results against common opponents would justify a deviation from the RPI. Perhaps in that context, the idea of rewards for wins/ties against top teams makes some sense.

Finally, the Committee has a rule that if it can't make a "bubble" decision after looking at teams' RPIs, head-to-head results, and results against common opponents, then it will look at the teams' last eight games and at the teams' results against other teams already selected for participation in the tournament. In looking at other teams already selected, however, the Committee must disregard results against automatic qualifiers with RPIs below 75. Since the RPI awards bonuses for wins/ties against teams with adjusted RPIs of 80 and lower, it seems odd for the Committee to have have used the 75th position as the one for excluding consideration of results against automatic qualifiers.

Every time you come out with a new slant on the regional analysis it just raises more questions about what the RPI really shows.

It also explains better why Basketball dumped The RPI as the sole prime determinant in selecting and seeding teams.

Just a quick note that Kennesaw State beat Mercer tonight. This is good, as Mercer is the Atlantic Sun regular season champion (due in part to a Kennesaw State loss to lowly Lipscomb, one of those games where the totally dominant team lost). Kennesaw State now is 11-4-4 going into the Atlantic Sun Tournament. So, Kennesaw's contribution to the Pilots' strength of schedule will go up. Plus, I think this may push them into the top 80, which means the Pilots also may accumulate bonus points for their win over Kennesaw at UW.

Hard to believe that I really care how the Kennesaw State-Mercer game comes out!

Further good news: Florida beat South Carolina 1-0 tonight. Apparently ugly, but Florida becomes the first team ever to go through the SEC pre-conference-tournament season 11-0.

Penn State lost to Ohio State today 1-0, with the stats being completely one-sided on Penn State's side. San Diego State also lost, to TCU, 2-1. USC beat Cal 2-0. UCLA is playing Stanford as I type.

Washington and Washington State tied 1-1 with stats looking like Washington had something of an edge. However, WSU's best player, who is on the U20 team, did not play. This outcome may be a plus in terms of hosting rounds 1 and 2 (the ideal is for Washington not to get a seed, as to which a tie is better than their winning the game; and for Washington State to win 2 of its last three games counting this one, as to which this counts as half a win so a win and a tie against the Arizonas next weekend probably would get them in). However, a Washington win would have been better for our RPI. And a Washington State win would have been better for our hosting rounds 1 and 2. Still, could have been worse.

Hard to say it, but GO UCLA

UPSF... in terms of hosting rounds 1 and 2, it really doesn't matter what seed we are as long as we are at least seeded 1-4. Hosting the later rounds it does matter, but I almost sense a certain perception that we won't host the first two rounds if we aren't a 1 seed. Not true... we'd host even as a 4 seed as long as a team in our geographical radius makes it.

The real key is UW NOT getting a seed.

UCLA beats Stanford 1-0 at home goal by Christina DiMartino. Stanford was clearly beating them with speed and offense but couldn't finish. Martino catches Keeper Marer flatfooted with a 30 yard strike.

DiMartino and M Rapinoe had their own epic battle at Merlo this season! She was one of the toughest opponents I've seen play against Megan....and Angie too. Undersized...but clearly a quality mid-fielder! During the Spring games when we played the U23s...they paired her with Brittney Klein of SCU. We were doomed.

GO PILOTS!!!

Stonehouse wrote:UPSF... in terms of hosting rounds 1 and 2, it really doesn't matter what seed we are as long as we are at least seeded 1-4. Hosting the later rounds it does matter, but I almost sense a certain perception that we won't host the first two rounds if we aren't a 1 seed. Not true... we'd host even as a 4 seed as long as a team in our geographical radius makes it.

The real key is UW NOT getting a seed.

Either UW not getting a seed or WSU getting an at large berth or PSU winning the Big Sky Tournament. But I agree with your main point. If another team from our area, without a seed, is in the tournament, then rounds 1 and 2 should be here. I'm being greedy. We want a #1 seed and all playoff games here until the Final Four. To the players, that's what the whole season has been about.

More good RPI news, in addition to UCLA's win over Stanford (which is good for the Pilots for other reasons, too). Northern Arizona beat Northern Colorado 2-1. And, Oregon beat Arizona State 1-0.

Today's (Saturday's) result not so good: Colgate lost to Navy 1-0. I was hoping for a Colgate win, but it was a longshot.

Tomorrow's games by our non-conference opponents: USC v Stanford is the big one -- Go USC!; UCLA v California, in which I root for UCLA; and Oregon v Arizona, in which I root for Oregon. If all three games go the Pilots' way, their non-conference opponents will have amassed pretty good results for the week. That will help, since adding Santa Clara's record to the Pilots' strength of schedule will not help, even if the Pilots beat the Broncos.

Let's make lots of noise at the game tomorrow.

GO PILOTS!

I anxiously await the RPI's. It might be that our rooting for UW may have done too much good. They are on the bubble to be seeded, and WSU may not make it.

ARGH!

Hey Geez,

What teams are in the drive zone for Stanford? Could they host?