How often does the best team win?

A couple months ago I asked how often the best team wins the world series. It turned out to be a surprisingly low percentage, and with the wacky final four I started asking the same questions about college basketball. Using the random chance in sports method to determine how often the best team won I calculated the probability of the best team being champion. Naturally it extrapolated itself to all sports:

NBA: 81%

This is by far the highest, and also the most wrong. Single teams don't distance themselves as often in the NBA, and some research I did in high school suggests that better teams win 60% of finals games, not 80%. Adjusting for that in the last two rounds puts the odds at around 48%.

College Football: 57%

People rag on the BCS, but I showed during BCS week that small playoffs are often better at selecting champions. Again, adjusting for using only the top teams and not the general random chance lowers the odds to 47%, which is still pretty high.

NFL: 55%

Even though this is the pro sport where the best team wins most often, single elimination hurts it. Byes help though (these odds assume the best team gets a bye). Assuming that the best team only wins .7 of the time (better for the playoffs) lowers the odds to 42%

You may be laughing now because I've corrected the random chance odds for each sport so far. It's much more accurate for the remaining sports though, either because top teams distance themselves farther (MLB and NHL) or because there is a full range of opponents in tourney play (MCBB and WCBB).

Women's College Basketball: 36%

We're probably a little thrown off because of UConn's recent success, but actually with 6 rounds of play even the women's tourney is ripe with upsets.

MLB: 33%

Series' are a necessity in a sport where even the worst teams win almost 40% of their games. The first round should probably become a best of 7 to help that out (it'd boost odds about 5%).

Men's College Basketball: 28%

We've seen this on full display in the tournament, as the clear best three (Ohio St, Kansas, Duke) have all fallen to lesser opponents. 6 rounds is fun though, so it's worth diluting it, but a 7th in the future would be a stretch.

NHL: 28%

This may seem weird with many former dynasties like the Canadiens, but in reality the modern day NHL is as full of parity as baseball, and with an extra round the best team's chances are the worst of any major U.S. sport.

Random Chance in Sports

This post is a followup to Random Chance in the NFL which highlighted the lowered competition in the NFL this year. It showed that the best teams win 62% of the time this year, far less than previous years. How often the better team won in previous years and in other sports were still left unknown though. Until now. Here, using the same methodology focusing on variance, here are the data on the last three full seasons in the four major american sports:

	2008	2009	2010
MLB	0.59	0.6	0.59
NBA	0.77	0.77	0.75
NHL	0.56	0.61	0.61
NFL	0.8	0.8	0.78

On average the better team wins 60% of the time in MLB, 77% in the NBA, 60% in the NHL, and 79% in the NFL. But how about this year? How often does the best team win in the NFL this year? It's gotten better since the last look, so far this year in the NFL the better team wins 70% of the time. While this is still an unprecedented increase in parity, it is also slowly getting closer to the norm we'd expect, thanks largely to big losers like the Bills and Panthers. So while this NFL season may have some crazy outcomes, it's still less random than sports like Hockey.

This article originally ran with a bug in the program used to calculate variance. While the effect on previous season results was minimal, it messed with the current season results a lot. The NFL is not actually just random chance this year, although going with just home field advantage would still be pretty good.

NHL Rankings!

NHL Power Rankings from 09-10 (kinda preliminary, some constants might be adjusted later).

Rank	Team	Record	PR	Schedule
1	Washington	54-28	1.971351978	0.897622912
2	Chicago	52-30	1.83689405	1.015734579
3	San Jose	51-31	1.604085453	1.04425634
4	Vancouver	49-33	1.60161888	0.997847038
5	Phoenix	50-32	1.284885124	1.046570781
6	Los Angeles	46-36	1.280345604	1.044849597
7	New Jersey	48-34	1.265161717	0.944877777
8	Buffalo	45-37	1.205482721	0.937670358
9	Detroit	44-38	1.1726501	1.063754376
10	Colorado	43-39	1.146104664	1.019181611
11	Pittsburgh	47-35	1.122893631	0.945574406
12	St Louis	40-42	1.094634453	1.04802023
13	Philadelphia	41-41	1.057873068	0.952982024
14	Nashville	47-35	1.034734645	1.055824315
15	Boston	39-43	1.014719416	0.948600448
16	NY Rangers	38-44	1.014680758	0.960645121
17	Calgary	40-42	0.988191313	1.033734957
18	Anaheim	39-43	0.945531872	1.069395612
19	Dallas	37-45	0.916399403	1.075699805
20	Montreal	39-43	0.891535366	0.947119358
21	Ottawa	44-38	0.828847814	0.952185525
22	Minnesota	38-44	0.815745702	1.057222185
23	Atlanta	35-47	0.775089497	0.955150235
24	Columbus	32-50	0.758758265	1.08525909
25	Carolina	35-47	0.743718177	0.958006177
26	Florida	32-50	0.695430488	0.973742079
27	NY Islanders	34-48	0.661466183	0.984849639
28	Tampa Bay	34-48	0.650924905	0.973139746
29	Toronto	30-52	0.59869451	0.975120685
30	Edmonton	27-55	0.568586705	1.076399338

Interesting to note is that you can tell whether a team is from the Western or Eastern Conference based off of only their strength of schedule (The Eastern Conference stinks). Darien loves it too.

RETRO PREDICTION: Blackhawks in 5. They win 79.3% of the time. It's okay this is just math so it's not biased by the wacky game 1. Go Blackhawks!!

Disaster!

Thank you Tyler Dawson for pointing out the failures of me.
"I enjoyed your blog post about the statistical likelihood of a sweep going into the second round, but like it even better now that there were 3 sweeps in this round."
Tyler Dawson is very smart.


It's true though, not only have the sweeps gone against my math, but so far I've gotten two out of three second round series' wrong, and am on pace to miss the third (what are you doing Lebron?!). Of course, I'd like to point out that I still had a 5% chance of a sweep for both the Lakers and the Suns. The Magic also had a 13% chance of sweep. That's missing the point though, because I still got pwned. At least the Blackhawks won (take that Darien and Stan!), so not all is wrong in the sports world.

Speaking of the Blackhawks, what are the odds that the Blackhawks win? Well, knowing what I know about hockey, and that they're in the semifinals, I'd say about about 25%. I guess it's hard to get really into hockey when you can't even ice skate. I'm just excited for my Byfuglien shirt.