The fifth-ranked North Carolina Tar Heels will close out their ACC regular season on Saturday the same way they always do — with a game against the Duke Blue Devils, ranked No. 17. The two teams’ longstanding feud is almost always mentioned first when people discuss great college basketball rivalries. But what’s in a rivalry anyway? A good one is a bit like a good obscenity — you know it when you see it. It’s an extra charge in the arena when the opponent comes to town; an unwillingness to give an opposing player the benefit of the doubt; a vilification of the other team’s coach as an evil mastermind.

But all that’s tough to measure, and measuring things is sort of the point of what we do around here. So I gathered data on some of the factors we can quantify, to put at least a few numbers on what makes Duke-Carolina so intense — and to see if any other pairings have the stats to contend with Tobacco Road’s finest for the sport’s top rivalry.

One obvious place to start is with the quality of the teams involved. I took every pair of teams that has played each other at least once every other season for at least a half-century, and sorted them by the average harmonic mean of the two teams’ Elo power ratings whenever they played. (I used the harmonic mean to make sure both teams hold up their end of the bargain in terms of high ratings.) By that measure, North Carolina and Duke have the fourth-best rivalry since 1950, which is when our dataset starts tracking Elo:

WINS ELO RATINGS TEAM A TEAM B SEASONS GMS TM A TM B TM A TM B HARMONIC MEAN Kansas Texas 1960-2017 33 26 7 2003 1847 1920 Arkansas Kentucky 1950-2017 38 11 27 1783 1988 1877 Kentucky Louisville 1951-2017 40 26 14 1919 1845 1877 Duke N. Carolina 1950-2017 174 81 93 1864 1876 1864 Indiana Kentucky 1966-2016 49 19 30 1838 1885 1857 Duke Michigan 1964-2014 30 22 8 1955 1775 1856 Kentucky N. Carolina 1950-2017 35 15 20 1834 1872 1849 Duke Georgia Tech 1956-2017 86 65 21 1963 1748 1846 Baylor Kansas 1952-2017 33 4 29 1728 1987 1844 Georgetown Syracuse 1958-2017 83 40 43 1837 1851 1842 Best college basketball rivalries since 1950, according to Elo Min. 50 years between initial and most recent meetings, and at least one game played every two years. Source: ESPN Stats & Information Group

Of course, rivalries are about more than just how good the two teams are. In the case of Duke-Carolina, it’s also about the sheer number of times they’ve played each other: 243 games in total (not including Saturday’s tilt), including 174 since 1950 — second only to the 198 editions of the “Civil War” staged between Oregon and Oregon State. And those games have been close, with UNC coming out on top overall, with a 93-81 record against Duke over the span of those 174 contests. In terms of proximity to a perfect .500 split, that’s in the top 18 percent of all 843 rivalries in our sample.

Proximity also plays a major role in Duke and UNC’s hostilities. Aside from the 14 rivalries in our dataset that involve teams from the same city — think Saint Joseph’s and Temple in Philly, or UCLA-USC in Los Angeles — North Carolina and Duke are the 16th-closest pair of schools, with only about 10 miles separating them.

Add it all up, and it’s difficult to find a rivalry that combines so many different measurable factors of animosity between two schools. None of the rivalries with an Elo rating in the same neighborhood as the Tar Heels and Blue Devils have played anywhere near as often , nor do any have the physical proximity, nor are any as closely matched recordwise. It’s a set of conditions custom-built for hate — and that’s without even considering less-quantifiable factors, such as the cultural divide between a public university (UNC) and a private one (Duke), the fact that most UNC students are from in-state while most Duke students are from outside North Carolina, or the many memorable incidents that have stoked the rivalry over the years.

RANK (OUT OF 843) ELO RK TEAM A TEAM B TOTAL GAMES PROXIMITY EVENNESS 1 Kansas Texas 792 784 772 2 Arkansas Kentucky 730 771 667 3 Kentucky Louisville 705 144 543 4 Duke North Carolina 2 30 155 5 Indiana Kentucky 613 288 436 6 Duke Michigan 823 750 703 7 Kentucky North Carolina 765 626 291 8 Duke Georgia Tech 378 643 736 9 Baylor Kansas 792 756 825 10 Georgetown Syracuse 401 560 82 11 Florida State North Carolina 518 741 788 12 Duke Notre Dame 834 772 729 13 Georgetown Villanova 456 251 205 14 Georgia Tech North Carolina 355 632 686 15 Arizona UCLA 338 705 287 Among top Elo rivalries, UNC-Duke stands out Source: ESPN Stats & Information Group

Saturday’s regular-season finale in Chapel Hill won’t serve as the de facto ACC regular-season championship, like it has at times in the past. (UNC can do no worse than a tie with Notre Dame for No. 1 in the conference standings, while Duke can’t win the conference.) But, as always, it will pit two of the nation’s top teams against each other in a preview of the kind of high-caliber matchup each squad will face on the road to the Final Four. And maybe that’s what stands out most about this rivalry: Both teams are always in the national championship hunt. (Famously, you have to go back to Feb. 25, 1955, to find a Duke-UNC matchup in which neither team was ranked nationally at tipoff.) So no matter who wins, we’ll be spending a lot of time with both the Tar Heels and Blue Devils over the next month.