The First Ever rAggie PI

rAggie · Post by **rAggie** » March 7th, 2011, 11:18 am

Here is the first ever rAggie PI, with spreadsheet attached for you all to analyze and help me refine.

Quick summary of the methodology:

AP and USA Today poll are each worth .3333 and are calculated by share of maximum votes each team received. I then took six computer polls, Live RPI, Sagarin, Sagarin Predictor, Sagarin ELO Chess, Ken Pomeroy and InsideRPI. I dropped the high and the low computer ranking from each team, took the average, subtracted it from 1 and then weighted it at .3333.

As far as this applies to USU...we're probably ranked right where we should be.

Rank Team rAggie PI

1 Ohio State 0.577189594
2 Kansas 0.393531443
3 Duke -0.567959278
4 Pittsburgh -0.808506612
5 SDSU -0.91653105
6 BYU -1.02169853
7 Purdue -1.625106826
8 Notre Dame -2.501287874
9 Texas -2.555482208
10 North Carolina -2.844496351
11 Wisconsin -2.901231448
12 Syracuse -3.169893873
13 Kentucky -3.41774971
14 Georgetown -4.31629392
15 Florida -4.612913131
16 Louisville -4.68058135
17 West Virginia -5.245496782
18 Utah State -6.01673569
19 Cincinnati -6.445226017
20 Arizona -6.595477214
21 Uconn -7.121391656
22 UNLV -7.237163059
23 Kansas State -7.463959937
24 St. Johns -7.722975628
25 Villanova -8.385037402
26 Vanderbilt -8.444868597
27 Xavier -8.929174443
28 Missouri -9.318919741
29 George Mason -9.408174833
30 Illinois -9.4999905
31 Temple -10.00733692
32 Texas A&M -10.9842255
33 Old Dominion -11.33106561
34 Washington -11.74955819
35 UCLA -12.39296688
36 UAB -13.33118949
37 Florida State -13.41579312
38 Georgia -13.4999865
39 St. Marys -13.66110179
40 Michigan State -14.1666525

rAggie PI.xlsx: (19.88 KiB) Downloaded 400 times

cache-aggie · Post by **cache-aggie** » March 7th, 2011, 11:21 am

very nice! But what, no love for the yahoo user ranking? j/k.

freakboy · Post by **freakboy** » March 7th, 2011, 11:38 am

Good Stuff. A couple of comments: Sagarin's overall ranking is a hybrid of Sagarin ELO (which only considers whether you won) and Predictor (which includes only the spread). I'm not really suggesting you drop anything, just FYI.

rAggie · Post by **rAggie** » March 7th, 2011, 11:40 am

Freakboy, if I could find a better sixth poll, I would drop the Sagarin rating. I just feel like I need to drop a high and low and don't want to do that with only five computer rankings.

SweepDance · Post by **SweepDance** » March 7th, 2011, 11:41 am

Not to nit-pick, but the Sagarin rating is an average of the ELO Chess and the predictior, so you're essentially duplicating those rankings. Another ranking you could try is bbstate.com. They have USU at #10, so I'm a fan!

Also, what's the difference between Live RPI and InsideRPI?

EDIT: Sorry, I guess I wasn't the first to point out the Sagarin thing.

SweepDance · Post by **SweepDance** » March 7th, 2011, 11:45 am

As a fellow nerd, I once created my own computer ranking for football (in an Excel spreadsheet), but don't have the time to do it for basketball. Too many teams, too many games, too much data entry.

rAggie · Post by **rAggie** » March 7th, 2011, 12:04 pm

I don't know what the difference between LiveRPI and InsideRPI is, but they are different.

freakboy · Post by **freakboy** » March 7th, 2011, 12:07 pm

I'd suggest adding Massey Ratings:

http://masseyratings.com/rate.php?lg=cb

It's included in the BCS ratings and is one of the best ratings at predicting the outcomes:

http://www.thepredictiontracker.com/ncaaresults.php

freakboy · Post by **freakboy** » March 7th, 2011, 12:21 pm

For the computer rankings, if you want them to be equal to 1/3 of the total ranking, then you need to come up with a better way of scaling the numbers. Right now, your polls are scaled between 0 and 1, but the computer rating score is scaled between -345 and 0. Maybe you should be subtracting from 345 (instead of 1) and dividing the whole thing by 344.

Better yet, do something like what the BCS does with their computer polls:

http://espn.go.com/ncf/news/story?page= ... anationnew

Six computer rankings calculated in inverse points order (25 for #1, 24 for #2, etc.) are used to determine the overall computer component. The best and worst ranking for each team is dropped, and the remaining four are added and divided by 100 (the maximum possible points) to produce a Computer Rankings Percentage. The six computer ranking providers are Anderson & Hester, Richard Billingsley, Colley Matrix, Kenneth Massey, Jeff Sagarin, and Peter Wolfe. Each computer ranking accounts for schedule strength in its formula.

You would need to drop any rankings less than 25 (or 35 or whatever you choose) and then give 25 for 1st, 24 for 2nd (or 35 for 1st if you keep 35, etc.) and then you'd have a total possible score of 125 (if you're keeping 5 ratings) or 175 if you're going with 35. Then calculate the percentage of 125 (or 135 if that's what you choose). Otherwise, you're putting essentially all the weight on the computer polls.

NAggsty Butler · Post by **NAggsty Butler** » March 7th, 2011, 12:21 pm

Interesting that sdsu still ranks ahead of byu.

Post by **AGinNEIowa** » March 7th, 2011, 12:30 pm

rAggie wrote:I don't know what the difference between LiveRPI and InsideRPI is, but they are different.

Freak - care to expound on this. I have the same question....

freakboy · Post by **freakboy** » March 7th, 2011, 12:38 pm

AGinNEIowa wrote:
rAggie wrote:I don't know what the difference between LiveRPI and InsideRPI is, but they are different.
Freak - care to expound on this. I have the same question....

I have no idea. I don't have access to InsideRPI, but if it's the same that they quote on the broadcasts, then it is not calculated using the same formula and/or they're classifying neutral/semi-neutral games differently.

Rabidchild · Post by **Rabidchild** » March 7th, 2011, 12:40 pm

AGinNEIowa wrote:
rAggie wrote:I don't know what the difference between LiveRPI and InsideRPI is, but they are different.
Freak - care to expound on this. I have the same question....

Since RPI is a discreet formula, I'm guessing any differences between LiveRPI and InsideRPI, or CollegeRPI or whatever, are merely computational errors by whichever one is off. I'd trust the Live-RPI, since I know its creator got straigth As along with me in our stat's class from Dave Bergenzer.

freakboy · Post by **freakboy** » March 7th, 2011, 12:44 pm

Rabidchild wrote:... in our stat's class from Dave Bergenzer.

That's what I'm talkin' about.

Post by **AGinNEIowa** » March 7th, 2011, 12:48 pm

Rabidchild wrote:
AGinNEIowa wrote:
rAggie wrote:I don't know what the difference between LiveRPI and InsideRPI is, but they are different.
Freak - care to expound on this. I have the same question....
Since RPI is a discreet formula, I'm guessing any differences between LiveRPI and InsideRPI, or CollegeRPI or whatever, are merely computational errors by whichever one is off. I'd trust the Live-RPI, since I know its creator got straigth As along with me in our stat's class from Dave Bergenzer.

straight A's?

I think I got about 70 on everything stats when I took it.

why use InsideRPI, if it's not correct?

Coloraggie · Post by **Coloraggie** » March 7th, 2011, 1:40 pm

Rabidchild wrote:
AGinNEIowa wrote:
rAggie wrote: our stat's class from Dave Bergenzer.

Start of the class every day was "Any questions on homework?" After a millisecond pause "Ok then, now let's suppose..."

BigVBAg · Post by **BigVBAg** » March 7th, 2011, 4:35 pm

This looks interesting. Here are some other rankings you could consider:

http://www.colleyrankings.com/hcurrank.html
http://warrennolan.com/basketball/2011/npi

This is also interesting as it compares 40 different rankings:
http://masseyratings.com/cb/compare.htm

rAggie · Post by **rAggie** » March 7th, 2011, 6:36 pm

Wow BigVBAg, I didn't know of that site that compiles all the rankings. That makes what I'm trying to do so much easier since you can download them into CSV.

Not every ranking on there is "quality", IMHO...so let's pick the rankings we want most in our own BCS rating for basketball...

40Aggie · Post by **40Aggie** » March 7th, 2011, 6:54 pm

What a bunch of numbers nerds. However, please keep nerding things up so we can all enjoy. Good work rAggie.

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