USING KENPOM'S PYTHAG AND LOG5 METHOD TO PICK AN NCAA TOURNAMENT BRACKET

by Joel on Mar 19, 2008 7:23 AM EDT in Tennessee Volunteer Basketball Comment 5 comments

After staring at A Sea of Blue's post setting forth the odds for each of the NCAA Tournament teams to win it all for a half an hour, I concluded: whoa, numbers. But once I recovered, I thought it would be interesting to see how each game of the bracket plays out using Ken Pomeroy's data. Below is the NCAA Tournament bracket, with each region on top of each other (as opposed to the four regions facing each other in groups of two) because who among us has a 34" computer monitor? The play-in game is on top and the final four is on the bottom. The four digit number immediately next to each team is that team's pythag, and the percentages next to the pythags are those teams' respective "chances of winning" that game. For instance, based on their respective pythags, Mt. St. Mary's should beat Coppin State 88.85% of the time and so we'll consider them the winner and move them forward to play North Carolina. Yes, you can get the same result by looking only at the teams' respective pythags, but I think the percentages give you a better feel for how those numbers might play out on the court.

A couple of pre-post observations from hooper:

Pythag uses "pace-neutral" weighting, which means it compares the ratios of point differentials but not the actual values of point differentials. For example, a team that averages 80 pts. for and 70 pts. against looks identical to a team that averages 64 pts. for and 56 pts. against. KenPom does this so he doesn't have to worry about how many possessions a team normally has in a game. But that does make a big difference in the play of a game. So you lose valuable data at the start. This is normal for every numerical method, but it's good to know what is being lost. What this means is that Kansas has had the best pts. for / pts. against performance per possession in the league. But we don't know how many possessions is ideal for Kansas, or even if it makes a difference.

We also don't know the uncertainty. For example, if a team has a "70% chance of winning", does that mean 70% +/- 15%, or 70% + / 5%? If it's the first, then it's not unreasonable to see an upset. If it's the second, then an upset would be a tremendous shocker. We don't have a feel for the significance of a point spread, in other words.

If anyone wants to update the table to account for any of that, have at it. Start here, then read this, then read this. In the meantime, though, have a look at the table below, all dressed up in pretty Easter pastels for your enjoyment.

Oh, and one more thing: I've entered this bracket into the RTT ESPN Tournament Challenge so we can keep track of how well it does. If anyone calls Ken Pom an idiot because this entry doesn't finish in the top spot, I will personally come over to his house, pull out his toenails with a pair of pliers one by one every hour on the hour, write "no, you're the idiot" on each one in pink fingernail polish, and feed them to him. And Jackson the Mule will be right behind me to finish you off.

PLAY-IN GAME
Coppin St.	.0984	11.15%	Mt. St. Mary's
Mt. St. Mary's	.4651	88.85%
EAST REGIONAL
North Carolina	.9739	97.72%	North Car.	.9739	68.35%	North Car.	.9739	60.04%	North Car.	.9739	57.00%	N. Car.
Mt. St. Mary's	.4651	2.28%
Indiana	.9453	64.62%	Indiana	.9453	31.65%
Arkansas	.9044	35.38%
Notre Dame	.9375	81.77%	Notre Dame	.9375	37.65%	Wash. St.	.9613	39.96%
George Mason	.7698	18.23%
Washington St.	.9613	91.16%	Wash. St.	.9613	62.35%
Winthrop	.7067	8.84%
Oklahoma	.9065	58.80%	Ok.	.9065	25.61%	L'ville	.9657	55.91%	L'ville	.9657	43.00%
St. Joseph's	.8717	41.20%
Louisville	.9657	94.66%	L'ville	.9657	74.39%
Boise St.	.6135	5.34%
Butler	.9164	71.24%	Butler	.9164	33.05%	Tenn.	.9569	44.09%
South Ala.	.8157	28.76%
Tennessee	.9569	95.66%	Tenn.	.9569	66.95%
American	.5016	4.34%
MIDWEST REGIONAL
Kansas	.9916	98.55%	KS	.9916	94.44%	KS	.9916	83.36%	KS	.9916	67.77%	KS
Portland St.	.6341	1.45%
UNLV	.8742	56.62%	UNLV	.8742	5.56%
Kent St.	.8419	43.38%
Clemson	.9593	77.09%	Clem.	.9593	75.48%	Clem.	.9593	16.64%
Villanova	.8751	22.91%
Vanderbilt	.8845	77.03%	Vand.	.8845	24.52%
Siena	.6955	22.97%
Southern Cal.	.9443	43.59%	Kansas St.	.9564	28.09%	Wis.	.9825	63.13%	Wis.	.9825	32.23%
Kansas St.	.9564	56.41%
Wisconsin	.9825	96.04%	Wis.	.9825	71.91%
Cal St. Fullerton	.6984	3.96%
Gonzaga	.9300	55.84%	Gonz.	.9300	28.84%	G'town	.9704	36.87%
Davidson	.9131	44.16%
Georgetown	.9704	96.35%	G'town	.9704	71.16%
UMBC	.5539	3.65%
SOUTH REGIONAL
Memphis	.9829	98.86%	Mem.	.9829	85.06%	Mem.	.9829	73.40%	Mem.	.9829	63.11%	Mem.
Texas-Arlington	.3980	1.14%
Mississippi St.	.9099	51.43%	Miss. St.	.9099	14.94%
Oregon	.9051	48.57%
Michigan St.	.9542	79.25%	Mich. St.	.9542	57.34%	Mich. St.	.9542	26.60%
Temple	.8451	20.75%
Pittsburgh	.9394	78.88%	Pitt.	.9394	42.66%
Oral Roberts	.8058	21.12%
Marquette	.9612	79.98%	Marq.	.9612	49.04%	Stan.	.9626	43.37%	Texas	.9711	36.89%
Kentucky	.8611	20.02%
Stanford	.9626	94.31%	Stan.	.9626	50.96%
Cornell	.6082	5.69%
Miami (FL)	.8860	49.80%	St. Mary's (Cal.)	.8868	18.91%	Texas	.9711	56.63%
St. Mary's (Cal.)	.8868	50.20%
Texas	.9711	97.54%	Texas	.9711	81.09%
Austin Peay	.4590	2.46%
WEST REGIONAL
UCLA	.9837	99.85%	UCLA	.9837	74.07%	UCLA	.9837	78.10%	UCLA	.9837	61.58%	UCLA
Mississippi Val.	.0846	0.15%
Brigham Young	.8929	28.30%	Texas A&M	.9548	25.93%
Texas A&M	.9548	71.70%
Drake	.9418	74.66%	Drake	.9418	48.88%	Conn.	.9442	21.90%
Western Ky.	.8460	25.34%
Connecticut	.9442	88.81%	Conn.	.9442	51.12%
San Diego	.6807	11.19%
Purdue	.9402	62.32%	Purdue	.9402	44.97%	Xavier	.9506	33.82%	Duke	.9741	38.42%
Baylor	.9048	37.68%
Xavier	.9506	82.69%	Xavier	.9506	55.03%
Georgia	.8011	17.31%
West Virginia	.9433	49.95%	AZ	.9434	30.68%	Duke	.9741	66.18%
Arizona	.9434	50.05%
Duke	.9739	97.41%	Duke	.9741	69.32%
Belmont	.4977	2.59%
FINAL FOUR
North Carolina	.9739	24.02%	Kansas	.9916	66.17%	Kansas
Kansas	.9916	75.98%
Memphis	.9829	48.78%	UCLA	.9837	33.83%
UCLA	.9837	51.22%

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Comments

Fatal Flaw?

Since the tourney expanded to 64/65 teams in 1985, there have never been all 4-#1 seeds in the Final Four. Kenpom's model predicts this will be the year. I hope it's wrong.

Makes me wonder though...IF UT could have pulled down a #1 seed, would the model have predicted them to make the F4? (Try just flip-flopping UT and UNC in the East bracket; see what happens.)

by Aerobab on Mar 19, 2008 8:24 AM EDT reply actions 0 recs

If UT had been in UNC's place,

this model would have them losing to Washington State. In fact, the only 3 teams in this Sweet 16 that UT would be favored to beat are Michigan State, UConn, and Xavier (according to this model). Even Clemson edges UT out.

This might sound strange, but it does teach something; UT cannot expect to win if they allow their opponent to run at peak efficiency. That basically describes the SEC tournament. UT's success is dependent on reducing the effectiveness of the opposition - steals, rebounds, and various and sundry forms of discombobulation.

by Hooper on Mar 19, 2008 9:47 AM EDT up reply actions 0 recs

Agreed!

I don't really understand formulas, but I do know about words, and the Vols gotta dicombobulate the heck out of their opponents to advance, and hopefully, win it all.

I just keep thinking that if they bring the intensity and focus and poise they took into Memphis, they can be the best team in the country.

Friday: American Hate Day! Oooh, that came out wrong...

by Volorado on Mar 19, 2008 2:38 PM EDT up reply actions 0 recs

All four No. 1 Seeds?

Based on this formula, all four 1 seeds advance. Only one small problem with that. It's never happened since the tournament expanded to 64 teams in 1985.

Memphis would probably be my guess for not making it to San Antonio.

My Signature Should be Better Than This

by MoonDogLeft on Mar 19, 2008 6:57 PM EDT reply actions 0 recs

True.

By its very nature, this process leaves out a lot of information. By this system, the only way a No.1 seed could get knocked out is if UNC was in the same region as Wisconsin.

Even though advancing all 4 #1 seeds hasn't happened yet, there's no reason it can't happen. It's not a scenario with a greater than 50% chance of occurring, but it probably has a greater chance of happening than any other combination of F4 teams. I'd guess Memphis too, but I'm really looking forward to seeing how this bracket does. Hopefully it doesn't make the rest of us look too bad.

by Hooper on Mar 19, 2008 11:09 PM EDT up reply actions 0 recs