Beginner's Guide to Bracketology Terms: NET, SOS and Other Useful Acronyms

It's early March, which means you cannot possibly watch men's college basketball games without encountering a staggering amount of bracketology terminology.

During games aired on ESPN's family of networks, there are constant references to Joe Lunardi's latest projections for the field of 68, often including live in-game interviews from his "Bracket Bunker." Games on Fox or FS1 will tout Mike DeCourcy's projections at least once every 10 minutes. The same goes for CBS with Jerry Palm's prognostications.

But if you're relatively new to the sport, you might just now be trying to figure out what in the world bracketology is while wondering how hundreds of different bracketologists can come to completely different conclusions from the same data. If so, you're in the right place.

This is my eighth season doing bracketology for Bleacher Report, and I've been obsessively trying to predict the NCAA tournament field for a solid two decades now. By no means am I the most accurate at reading the minds of the selection committee, but I am at least more than qualified to explain some of the primary words and acronyms used in the inexact science of projecting the field.

Team No. 1: Bracketology

Best begin at the beginning by defining bracketology itself.

A lot of people seem to think bracketologists are uniquely skilled at predicting what will happen in the NCAA tournament, but that's not what the title means. In fact, it is often the furthest thing from the truth. To the contrary, bracketology is the art/science/process of predicting what the bracket will look like on Selection Sunday.

Not only do we attempt to project which 68 teams will make it into the NCAA tournament, but we also use the NCAA's seeding and bracketing principles to try telling you exactly where each team will be placed.

For example, a bracketologist can tell you Gonzaga will most likely be the No. 1 seed in the West Region, playing its first two games in Spokane, Washington. But a bracketologist is not necessarily the best person to consult if you're wondering whether it's a good idea to pick the Zags to advance to the Final Four.

Now that's out of the way, here are some of the primary metrics and acronyms that bracketologists spend most of their time looking at.

Term No. 2: NET

We're not talking about the braided nylons hanging below the rims. Rather, this is the acronym for the NCAA Evaluation Tool (NET), which replaced Rating Percentage Index (RPI) as the primary metric used to rank teams. (If you don't know what the RPI is/was, don't worry about it. It's dead and gone and never coming back.)

Per the NCAA website, NET is a combination of four factors: team value index, net efficiency, winning percentage and adjusted win percentage.

Team value index is the results-oriented portion of the equation that factors in strength of opponent, who wins and where the game is played. Net efficiency is basically just per-possession scoring margin, but it is capped at 10 points so as to not encourage teams to keep throwing down dunks with their starters in a 30-point blowout. Winning percentage is simply that, and adjusted win percentage factors in the location of the game: Road wins are given extra credit, and road losses aren't penalized as harshly.

How those factors are actually weighted and combined to spit out a daily ranking of the 353 teams is anyone's guess. The NCAA worked with the selection committee, coaches, basketball analytics experts and Google to come up with some top-secret formula it won't release to the public.

The general idea is that this is a better predictive metric than RPI, though, which most basketball fans and experts would agree is a good thing even though we aren't privy to the ins and outs of it. It's not perfect, but if you're good and beat good opponents, you're probably in good shape in the NET. And that NET ranking is the backbone for all tournament resume information.

While it is the backbone, it is not the be-all and end-all. North Carolina State was left out of last year's tournament despite a respectable NET ranking of 33rd. St. John's got in with a NET ranking of 73rd. Think of NET as more of a starting point from which the selection committee will move a team up or down based on other factors.

Term No. 3: Resume

Jeff Chiu/Associated Press

Just like a job resume, a team's tournament resume (or team sheet) is a one-page snapshot of everything it has done to deserve (or not deserve) consideration for the NCAA tournament.

Resumes are broken down into four quadrants (more on that term shortly), which is extremely helpful in quickly identifying good wins and bad losses.

Other tidbits of information on a resume include NET ranking, strength of schedule (another soon-to-be-defined term) and records by location.

One big thing not included on a resume is conference record.

Fans love to bring up the conference records of various teams when arguing about seeding or selection, but it doesn't matter. The selection committee looks at the full body of work, which is obviously influenced by a team's successes and failures in league play, but its members are never going to say, "Well, we should give some more credit to this team because it finished in the top half of the [insert major conference]."

For proof of how much conference record doesn't matter, look at the 2017-18 Pac-12. USC finished in sole possession of second place with a 12-6 record and didn't make the NCAA tournament, but Arizona State went 8-10, was the No. 9 seed in the conference tournament and got an at-large bid.

Term No. 4: Quadrants

As previously mentioned, each game falls into one of four quadrants, which are based on a combination of the opponent's NET ranking and the location of the game. Here's the breakdown:

• Quadrant 1: Home games vs. NET Top 30, Neutral-site games vs. NET Top 50, Road games vs. NET Top 75
• Quadrant 2: Home vs. NET 31-75, Neutral vs. NET 51-100, Road vs. NET 76-135
• Quadrant 3: Home vs. NET 76-160, Neutral vs. NET 101-200, Road vs. NET 136-240
• Quadrant 4: Home vs. NET 161-353, Neutral vs. NET 201-363, Road vs. NET 241-353

Quadrant is a relatively new term that was put into place prior to the 2017-18 season. We had the four-buckets idea for a while, but the games used to be placed into groups—RPI Top 50, RPI 51-100, RPI 101-200 and RPI 201-plus—without accounting for the location.

In that previous bucketing, a home win over the 50th-best team looked the same (from a bird's-eye view) as a road win over the No. 1 team. The latter certainly counted for more, but when we would spout off about a team having "X RPI Top 50 wins," the X counted at No. 1 and vs. No. 50 as equals.

The new system does a better job of categorizing quality wins and bad losses.

On its nitty-gritty team sheets, WarrenNolan.com (my daily go-to for all bracketology research) even goes one step further, breaking Quadrants 1 and 2 down into a top half and a bottom half. If nothing else, this helps identify which quality wins were of the highest quality and which results were closest to the various cut lines and most likely to move to a different quadrant.

To that end, be sure to note that a Quadrant 1 win isn't permanently a Quadrant 1 win. Here's a potentially significant example from this year's bubble: Richmond's Jan. 14 road win over Davidson was a Quadrant 1 result on Tuesday morning. But after Richmond beat Davidson by 17 at home that night, the Wildcats dropped from NET No. 74 to No. 76, bumping Richmond's previous win down to Quadrant 2.  

Term No. 5: Strength of Schedule (SOS)

Michael Conroy/Associated Press

Strength of schedule is a means of ranking teams by the difficulty of the paths they have taken*, and it is sort of baked into everything else.

SOS shows up on each resume, it is factored into the NET's team value index, and it can be more or less inferred from discussions about quadrants. For instance, Kansas has played 14 games against Quadrant 1. Gonzaga has played 10 each against Quadrants 3 and 4. One doesn't need to know the ins and outs of how SOS is calculated to know the former has faced a much tougher schedule than the latter.

Because it is already an ingredient of the metrics, we don't often look at it as a standalone data point.

The exception to the rule is when a team has a particularly bad nonconference strength of schedule (NCSOS).

Among the teams that are at least in the conversation for an at-large bid, this year's biggest offender is Penn State. The Nittany Lions played 11 nonconference games, five of which were at home against Quadrant 4, including two against the especially bad Maryland-Eastern Shore (NET No. 350) and Central Connecticut (NET No. 347).

While almost every team has a couple of nonconference cream puffs on its schedule, it's important to balance the scales with a few Quadrant 1 games. Penn State neglected to do so. Wins against the likes of Georgetown, Alabama and Syracuse were OK, but the Nittany Lions did not play a single nonconference game against a projected at-large team, which is a great big no-no for the selection committee.

Even though the rest of Penn State's metrics look good, the committee almost always penalizes teams with an NCSOS outside the top 300. The Nittany Lions are hovering around No. 330 in that category. It won't keep them from earning a bid, but it might cost them a couple of seed lines.

Teams also often get rewarded or forgiven for putting together a challenging NCSOS. LSU, for example, doesn't have a single great win, but a top-10 NCSOS has kept the Tigers more than afloat.

Aside from those two extremes, though, SOS doesn't usually receive much attention.

Term No. 6: Automatic Bid/At-Large Bid

We'll finish with an easy one.

There are 68 spots in the NCAA tournament field. Thirty-two are awarded to the winners of the conference tournaments, and 36 others are at-large qualifiers deemed worthy of an invitation despite not winning their conference tournament—sort of like the wild-card teams in MLB or the NFL.

The automatic/at-large designation only applies to selection, not to seeding. In other words, at-large teams don't need to be seeded lower than the automatic bids. In fact, it's somewhat common for No. 1 seeds to be at-large teams.

[Bonus term: Bid Thief. This is when a team that wouldn't be expected to get into the tournament with an at-large bid surprisingly "steals" an automatic bid in a conference with at least one other tournament-bound team. This forces a projected auto bid into the pool of 36 at-larges, which shrinks the bubble. For instance, if North Carolina miraculously won the ACC tournament this year, it would be a bid thief.]

Up until the conference tournaments, the automatic bids are projected to go to either the best team or the one with the best conference record (depending on who you ask).

But whereas those professional wild-card teams are based entirely on record and predetermined tiebreaker scenarios when necessary, the 10-member selection committee is tasked with choosing (and subsequently seeding in order) the best at-large candidates based on a group discussion about what each member feels is most important.

This intentional vagueness regarding criteria is why three well-respected bracketologists can have diverging opinions about where a certain team should be placed. All three could end up being wrong.

Our job as bracketologists isn't to tell you what we think should happen, but rather what we think the committee will decide. And considering up to five of the 10 committee members are replaced each year, what seems most important one season is liable to change during the following one.

So there you have it.

There are plenty of other terms and websites worth knowing, but you can pick those up along the way. If you've got a firm grasp on NET, resume, quadrants, SOS and auto/at-large, you're pretty much ready to become an amateur bracketologist. At the very least, you'll have a much better understanding of all the blind resumes and "Last Four In" banter with which you'll be inundated until Selection Sunday.

*Other metrics like KenPom.com and ESPN's Basketball Power Index (BPI) will have different SOS rankings because the calculations are based on their team ratings. However, a terrific/dreadful strength of schedule tends to be terrific/dreadful regardless of the source.

Kerry Miller covers men's college basketball and college football for Bleacher Report. You can follow him on Twitter, @kerrancejames.