Explain basketball tournament brackets to me

OK, I understand the basics of single-elimination tournaments and seeding, but I have noticed what, to me, are some peculiarities in recent college conference tournaments and the current NCAA men’s tournament.

Let’s say we have 16 teams in a tournament, and they are seeded (by whatever criteria) from 1 to 16. So in the first round we’d have 1 vs 16, 2 vs 15, 3 vs 14 and so on. If there were only 15 teams, normally 1 would get a first round bye because there would be no 16, and the rest of the teams would play 2 vs 15, 3 vs 14 and so on as before. Team 1 would then play the winner of 8 vs 9 in the second round. With 14 teams 1 and 2 would get first round byes and the rest would proceed as before, with 1 playing the winner of 8 vs 9 and 2 playing the winner of 7 vs 10 in the second round. At least that is what I’d expect.

But that was not the case in the recent 14-team Big 10 and SEC tournaments (and maybe others as well). In both those cases* four *teams, 1 thru 4, got first round byes and didn’t play until the third round. When did this start and what is the reasoning behind it?

The big NCAA tournament starts with 68 teams, so there are four play-in games, one for each regional bracket. The winners of two of these games enter their regional bracket as the 16 seed, as I would expect. But the winners of the other two games enter their brackets as the 11 seed. Why don’t all four enter as 16 seeds, and when did they start doing it that way? What is the reasoning there?

Short answer: money.

Long answer: I’ll defer to more articulate posters.

With only 14 teams, there’s a much higher chance of a low seed knocking out a high seed early.
The skill differential is much closer than with 64 teams.

I’m not sure how this would work. I guess if there 14 teams and 4 got two byes, then you’d have to give 6 first-round byes to the remaining 10 to make an effective 16 teams then play two rounds to reduce that to 4, then merge the other 4 back in. Is that what they did?

In any case the number of teams + the number of byes has to equal a power of 2 unless it’s double elimination.

The SEC and Big 10 brackets had two sets of byes. Teams 6-10 got a bye to the 2nd round, and teams 1-4 got a bye to the third round. So the first round consisted of just two games - 11v14 and 12v13. The two winners joined teams 6-10 to make 8 teams for 4 games in the second round. Those four winners moved on to face teams 1-4 in the third round.

what happened to #5?

mc

I think that should have been “5-10 get a bye to the second round.”

The “First Four” opening round has been in place since 2011. Before that, since 2001, there was one opening round game and the winner of that game was a 16 seed. When it was expanded to 4 games, two of the games remained a competition for a 16 seed while the other two games were a competition for a higher seed. In this case, those two games are meant to be between the last four teams considered for an at-large berth into the tournament. Since the 15 and 16 seeds are always taken by automatic qualifiers who won their conference tournament but are not expected to be competitive against the big kids, two of the opening round games end up vying for a 11-14 slot.

the ACC also has top 4 teams skipping the first 2 rounds but the ACC has 15 teams for BB. Notre Dame is a member in all sports except FB. They did agree to play 5 ACC teams every year in FB , the teams rotate.

OP here. Thanks for the replies, but none have provided a clear explanation of WHY the brackets are structured the way they are, especially the reason for playing in for an 11 spot. ISTM that with 68 teams in the tournament, teams seeded 65 to 68 should be playing to enter at a 16 spot. Why should they enter at anything higher? And why specifically 11?

NCAA tournament: Why are there play-in games for 11 seeds?

Yeah, I thought I did explain it enough, because the longer explanation is difficult to type out without alot of background.
It really comes down to the fact that 32 teams get automatic bids to the tournament, and 36 are invited by the committee. The vast majority of those 32 teams are teams like UMBC that have no chance of winning any games because they are from a small conference, or teams from a larger conference who managed to win their conference tournament but otherwise would not have qualified for an invitation. Those teams take up the majority of the 12-16 seeds.
The “first four” games consist of four teams at the bottom of each of the two groups - the last four automatic qualifiers, who play for two of the 16 seeds, and the last four of the invitees, who play for the bottom seeds available after the AQs are slotted, which in this case ends up being 11.

The NCAA could have made all four games for the 16 seeds, but one of the complaints when the “opening round” was 1 game for a 16 seed was that it featured teams from small schools who had earned their way into the tournament, but then one of those teams loses in a game in Dayton and never gets to experience the tournament proper. The current setup was a compromise to avoid the idea that 8 of the automatic bids were just meaningless invites to meaningless games held before the actual tournament started.

Thanks. That was a much better explanation for the NCAA tournament.

As for the structure of the conference tournaments (in the case where teams 1-4 get two rounds of byes vs teams 1-2 getting one round of byes), I would guess that it reduces the probability that any of teams 1-4 get knocked out early, and the conference ends up getting represented by an underling. Is that really it?

BTW are there any 16-team conferences, and do any of them distort their brackets this way?

I looked through the brackets here https://www.cbssports.com/collegebasketball/schedules/conference-tournament and did not see any 16 team tournaments this season.

Of possible interest to you, the OVC and Southland Conferences each hold 8 team tournaments where the 1 and 2 seeds are byed all the way to the semifinals. While some of the other formats can be explained away in that it’s messy to draw up brackets for 14 or 15 teams, these brackets are clearly designed to protect the top seeds and increase their chances of earning the AQ bid.

Another reason to give two layers of byes in 13-16 team conferences (or play-in games into a 12-team tournament, if you prefer) is that if you didn’t want to give anyone serious rest disadvantages, you would have to play six games in one day. That’s about 12 hours of game time and 3 hours of mandatory warm-up time for the teams, which causes a problem for facility staffing and television. (That’s a little bit about money, I guess.)

Before the Big East spawned the American conference, they had 16 teams. IIRC, 1-4 got a double bye and 5-8 got single byes. This made for a nice 4 games per day at Madison Square Garden for the first three days.

There are two main reasons for tourneys being structured the way they are structured.

1 - The advertised reason is the bigger advantage for the better team. You can build a bracket that has 1v8, 2v7, etc which obviously does give an advantage since the better teams play the worse teams. But, in a deep league like the Big 12, the 8th best team is actually decent and an NCAA tournament worthy team as well. So, simply getting to play the 8th best team is nice, but it’s not exactly a walkover. Same things happen in youth tourneys, pros, etc. The gap between first place and Xth place might not be that consequential. That’s why you also see the added advantage in pro league of having more home games for the higher seeded team as a secondary advantage. In a tournament type one game winner take all setting, the high variability increases the odds a lower seeded team might win. Take the Virginia UMBC game. Have those teams play 100 times. I’d bet that Virginia wins 98+ times. But, this one time happened to include inferno level shooting in the second half for UMBC, completely awful shooting from Virginia, stress killing the UVA players, etc. So tourney oftentimes give extra byes to higher seeded teams as a further reward for their full season body of work.

2 - The main reason is money. This comes into play a couple of ways. Let’s say you are the SEC. Your best team is Kentucky - national powerhouse, fans travel insanely well, tons of press coverage, everyone knows them. Your 8th best team is Mississippi - no real history of success, I dare you to name their best player or coach, fans won’t really travel, twitter won’t take about them. You want to do what you can to get Kentucky it’s best shot at being in the tourney as many days as possible for the revenue, publicity, word of mouth, etc. So, instead of Kentucky having to play the 8th seed day 1, you give them a bye. They play the winner of the 4v8 game on day 2 so they get a little more rest, more chances to scout, and an enhanced advantage. The other monetary impact is that by making a tourney with more bye rounds, you will likely increase your tourney from a 3 day to a 4 day event. Extra ticket sales have to happen. More merchandise and food is purchased. You get extra time on TV and in media. All of that adds up to cash. If you are a big conference like the ACC, you know that any cost of running a tourney for 4 days instead of 3 is going to be wildly outpaced by the incoming revenue of thousands of fans flocking to the event. If you are a smaller conference, you don’t have that luxury, so you might be more likely to keep it conventional.
Long story short, if the NCAA is involved, they will give lip service to competition, but the real answer is money.

It’s not just “the bigger advantage for the better team”, although there should be a reward for regular season and post conference tournament success. It’s also a matter of fairness as in it is NOT fair to have two powerhouses play each other in the first round while two relative weaklings are playing each other in the first round because that would mean one of the powerhouses would have to be eliminated and one of the weaklings would have to advance.

Besides, if the weaker team like UMBC does beat the stronger team like Virginia, it takes the place of the stronger team in the bracket and continues with the draw that the stronger team was going to inherit if it had won. It really is the fairest method of doing it.

Now, the precise seeding is another matter. That’s a matter of judgment by the committee, and there is always grumbling every year as to the accuracy and fairness of the seeding process. There’s no way around it, though, because many of the teams chosen have not played many of the other teams head to head, so it’s pretty much based on how strong a given conference is perceived to be, how tough a team’s non-conference schedule was perceived to be, how well a given team was playing at the end of the season, etc.

Nitpick: ND is in the Big Ten for hockey only.