Who’s the best around? It’s a question that fires up MMA fans and while best debated all night over rounds of drinks, is also an opinion-based question that, as Bill Clinton would say, depends on what the definition of “best” is.
Even with “best” defined, people can still dig-in to an opinion and refuse to budge if they so choose. But that doesn’t mean analytics can’t throw its hat into the ring and add a little to the discussion.
The version of “best” we’re going to use is “most dominant.” Not most dominant at this moment in time, but observed dominance over all fully-documented Zuffa fights. For instance, many people have UFC flyweight champion Demetrious Johnson as their pound-for-pound best fighter in the world today. But has he shown consistent dominance over time, day after day, fight after fight? While he’s been on a tear lately, his poor or close performances against Brad Pickett, Miguel Torres, Dominick Cruz, and Ian McCall will come back to hurt him a bit. Three out of four of those fights were admittedly in the wrong weight class for DJ, but we’re basing this exercise off what each fighter has actually shown inside the cage, not how we think they would’ve performed in different circumstances.
For metrics, we’re not interested in how much the other guy bleeds or how many more significant or power strikes a fighter lands. Our working definition of dominance will be, “During each bout or round, how obvious was it that a particular fighter won?” Basically, the more someone exerts their will over an opponent, the more that performance is called dominant. Writer’s note: I’m open to the idea that this may not always hold true (e.g., lay-and-pray victories) but also believe it’s a pretty strong relationship in general.
If a fighter gets beat up for two rounds but knocks out or submits his opponent in the third, was this dominant? Isn’t the goal to win the fight? There’s not a much clearer victory than beating someone to the point of defenselessness or making them say Uncle. From one perspective, perhaps this is dominant. From another perspective, perhaps dominance is observed in consistency, exerting one’s will round after round after round.
To account for different views of dominance, it will be measured in two ways: bout-by-bout and round-by-round. In the bout-by-bout version, a fighter is given 100 points for a clear finish victory, zero points for a finish loss, and 100 * RoboJudge’s probability of victory if the bout goes to a decision. For example, if we go to the scorecards and a fighter has a 60% chance of getting the decision, their performance wasn’t clear-cut regardless of whether they end up winning or losing. They didn’t destroy the opponent, but their performance was worthy of a slight edge and therefore earns a dominance score of 60.
The round-by-round version is similar except a fighter earns 100 points for a finish win in a round, zero points for a finish loss in a round, and 100 * RoboJudge’s probability of winning the round if they make it all the way through. In this version, if a fighter gets a knockout in the third round but took massive damage in the first two, he didn’t put on a dominant performance.
We’re interested in observed dominance but also want to limit the results from people who may beat up on lower-tier fighters. For that, we only analyze fighters with at least eight fully-documented Zuffa bouts. Weight classes are assigned using the statistical mode, meaning each fighter is assigned to the weight class in which they’ve taken the most bouts. In the case of a tie, the lower weight class is used.
Since Rousey’s won all of her fights by knockout or submission, she automatically earns the top spot. It doesn’t get any better than Ronda for clear-cut victories, and Jose Aldo and Chris Weidman aren’t too shabby either. Ronaldo “Jacare” Souza breaks into the Top 10 as he’s torn through opponents not named Luke Rockhold. His days of putting a beatdown on Chris Camozzi are officially over, though, so we’ll see if he’s truly earned that spot in short order.
A few things change when analyzing round-by-round, but Rousey’s utter dominance isn’t one of them. Remember the first round of her rematch with Miesha Tate? She had a 98.9% chance of winning that round and it was the worst of her Zuffa career. That, my friends, is insane.
Rounding out the top, T.J. Dillashaw’s consistency is rewarded round-by-round and Cain Velasquez has pretty much only had three bad rounds in his Zuffa career.
Now let’s see how Rousey compares not against the Top 10 but against all Zuffa fighters who’ve had a long enough career to make the cut. The visual lesson: Ronda’s a beast, especially round-by-round. It’s much easier for top fighters to win bouts convincingly than it is to convincingly win every round. The distribution of dominance noticeably shifts down when measured round-by-round, yet Ronda’s data point remains virtually unchanged. Normal human beings slip up every once and a while, at least for a few minutes here and there. But in Rousey’s world, anything less than a 98% chance of winning a round is sloppiness that shall not be tolerated! In statistical terms, the graph on the right is just plain sick.
Rousey’s absolute dominance is impressive. So how does she stack up in a relative sense, comparing her performances to the next best fighter in her division? I call this the Dominance Gap. It’s measured as the percent increase in the top fighter’s dominance over the second best fighter in each division.
While the Zuffa women’s bantamweight division is relatively young in terms of taking eight or more bouts, we’ve got complete data on the champion and the #1 contender. It’s enough to compare to the other divisions and the results are, once again, statistically sick.
Since I didn’t show the complete table, readers couldn’t see that the first lightweight fighter in round-by-round dominance doesn’t show up until #26. These guys just seem to beat up on each other. Whether we want to call it Zuffa’s toughest division or a division without a longstanding champion to separate from the pack, it makes sense why some unexpected names can get towards the top.
In Rousey’s division, #1 contender Miesha Tate has had a tough time exerting her will on opponents, yet Ronda’s steamrolled through everyone. Divisional legends such as Jon Jones, Georges St-Pierre, and Jose Aldo can’t crack a dominance gap of 25% while Ronda’s up above 95% enjoying the view.
What did we learn? Ronda Rousey’s an anomalous, statistical freak of an outlier. That’s a technical term and I am a professional.
It’s time to put these numbers to bed and enjoy every precious second we get of Rousey doing her thing inside the cage. Be sure to follow all the UFC 193 coverage right here at Bloody Elbow throughout the weekend. Enjoy the fights!
Paul is Bloody Elbow’s analytics writer. All mistakes are his own and they’ve been known to happen sometimes. Follow him at @MMAanalytics. Fight data provided by FightMetric.
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