The Hard Numbers on the Small UFC Cage (Part 1)

Analysis of cage size effects was presented in the “Fightnomics” book, this analysis is more recent and focuses on UFC competition only. 


What if you had your own MMA promotion? You could manage your own roster and even tweak some of the rules to orchestrate the perfect fight card. What would you change to maximize your objective of offering fans the most possible excitement? Would you focus on certain weight classes, or change the rules to allow soccer kicks? Would you invest in cutting edge audio and visual bells and whistles for enthralling fighter walk-ins? Or just cut all unnecessary costs to sign the highest profile fighters? Maybe the two-on-two Russian regional rules are a little too extreme, but would you consider a one-night, eight-man tournament bracket? What about announcers, ring card girls, or a live band? Let’s consider something far more fundamental, something right under our feet that doesn’t even cost much to change. If reducing the size of the cage isn’t near the top of your list, you’re missing out on one of the easiest ways to increase excitement with little additional cost.

In my book “Fightnomics”I revealed a secret hidden in the UFC’s integration of the World Extreme Cagefighting promotion in 2011: the cage sizes were different. The blazing blue cage of the WEC that launched the careers of Urijah Faber and Jose Aldo was only 25 feet in diameter, while the full-size Octagon of the UFC spanned 30 feet. So I did a little analysis of WEC and UFC fights in the same divisions and found a big difference in finish rates and the pace of fighting. Specifically, the smaller cage of the WEC saw faster-paced fights that were much more likely to end early than when the same fighters fought in the larger UFC Octagon.

The idea that the cage size could impact how fighters perform in MMA didn’t seem all that crazy to me, and since posting the results of the analysis it has become far and away the most viewed article ever on my blog. It seems to confirm conventional wisdom that placing fighters in a smaller arena gives them less room to roam and increases the intensity of the competition. Yet some to this day brush off the idea, thinking that the smaller cage just means more time spent clinching up against the fence, or that the total fighting space simply has no effect on fighters. No one finds a slow, stalling clinch exciting, and if there’s no effect, then we can drop the subject and let cage size simply be optimized towards other objectives, like fitting more sponsor logos or improving camera angles. It’s safe to say a smaller baseball field would yield more home runs, but more questionable to guess about the effect of a smaller soccer pitch, or hockey rink. With differing opinions, and before we can look at the underlying causes, we must first understand the actual effect.

And we finally can. Over the last two years, the UFC’s previously rare use of a small cage only at Finale events for “The Ultimate Fighter” TV show has changed. The small cage started popping up on the military bases hosting Fight for the Troops events, and then at more mainstream (albeit small) venues for UFC Fight Night events. In recent months some MMA media members have taken notice, often announcing that a small cage will be in use for an event, or even lamenting the lack of one when a card features a lot of fights ending in decisions. I’m flattered my crazy theory is finally gaining acceptance, but it assumes that there’s a measurable difference. While the prior analysis focused on the differences between WEC and UFC finish rates by weight class, we now have an even more consistent population of fights to compare within the UFC alone. The new analysis will remain in one promotion, with stable rules, matchmaking, time periods and fighter rosters.

Difference in Cage Sizes

The difference of five feet in cage diameter may not seem like a lot, until you calculate what that means for the fighters standing inside it. The wider cage creates 44% more surface area in the larger Octagon, a cavernous difference for the smaller weight classes that moved into the UFC from the WEC. Conversely, seeing the rare Heavyweight matchup in a small cage is as close to the “fighting in a phone booth” analogy as you’ll ever see. Recently, Matt Mitrione was asked about the small cage at the UFC Fight Night 50 event at the Foxwoods Resort in Connecticut. The venue only seated 4,000 fans, less than half the normal arenas for FOX or Pay-Per-View events, and tight quarters required a small cage despite two heavyweight bouts on the main card. Mitrione commented on the noticeable and impactful difference the small cage has on his fight game. “I’d rather fight in a field than a phone booth,” Mitrione concluded after that fight. While he was not a fan of having less space to roam despite having won the fight in just 41 seconds, other fighters like Tim Kennedy prefer the smaller cage because it allows an aggressor to cut off a circling opponent more easily. The small cage may have helped Kennedy catch and knock out a circling Raphael Natal at their Fight for the Troops matchup during which Kennedy was hiding a torn hamstring. Regardless of preference, the question remains: what really happens in MMA when a smaller cage is used?

Let’s find out.

Size Matters in MMA - fightnomics-p

The first thing to understand when analyzing UFC finish rates is that size matters…most of the time. When looking at UFC fights ending inside the distance before the WEC merger, a very clear positive correlation between fighter size and finish rates was observed. Imagine only viewing the right half of the chart above; from 155 pounds up to 265 pounds it looks like the bigger they are, the harder they fall. But it turns out that there’s a lower limit to MMA finish rates. Once the lighter weight classes joined the UFC, many observers (including myself) believed we would see a precipitous decline in the overall finish rates because fewer and fewer fighters would finish fights as the competitors got smaller and smaller. However, now with several years of data to observe, it appears that there is actually a floor to finish rates in the UFC regardless of size.

The results above show that the minimum finish rate for a single weight class over the last five years is actually in the Featherweight division at 42%. The Women’s Bantamweights are just above that at 43%. The Flyweights, who perhaps draw the most ire for lacking KO power, actually finish 46%, while the men’s Bantamweights impressively finish fully half of their fights at 50%. Only Middleweights and above finish more than half of their fights, and the obvious outliers are the KO-loving Heavyweights who finish 74%. As one would expect, the big difference between small and large fighters is knockout power, with the heavier fighters ending many more fights by T/KO than the smaller ones. There’s also a slight tradeoff with submissions, as smaller fighters end more fights by submission than larger ones, just not enough to overcome the big difference in knockouts.

So size matters, but then eventually it doesn’t. The mean finish rate for the stable divisions from Flyweight through Welterweight is 46%. When larger fighters step into the cage in the three heaviest divisions, then we see a sudden increase in finish rates. Understanding this trend is important to comparisons of finish rates by some other variable, because larger fighters continue to carry more value to the UFC. The largest fighters are more likely to be placed on the main card of a UFC event, and even earn more in base salaries on average.

Well, that’s enough build up. Let’s see if small cages really do boost the action in MMA.


The high-level look at finish rates suggests a difference in finish rates in different cage sizes. The average finish rate for the large cage during the period of analysis was 48%. The large cage had an average fighter size of 167.8 pounds, placing the “average” UFC fight just below the Welterweight division limit. In the small cage UFC events, however, the finish rate jumped to 60%, despite fighters competing with an average weight closer the Lightweight division at 161.9 pounds.

So is that jump from 48% to 60% a big deal? Yes, I believe that it is. First, the UFC hasn’t seen an average finish rate of 60% since the year 2009, when the center of mass for the promotion was closer to Middleweight, and the UFC put on just a fraction of the cards and fights that they do now. The difference between 48% and 60% translates to 1.4 additional finishes per 12-fight card. And again, it would be higher if the same weight distributions were used in both cages, which they are not currently. If we normalize the weight class distribution of fights to be identical and assume the same finish rates per division and cage size, the small cage finish rate bumps a little further to over 62%. That leads to 1.7 additional finishes per fight card. Imagine at each UFC event there was an additional knockout and submission highlight for the evening. Every time.

The average fight duration shows that small-cage fights are 58 seconds shorter on average. There are some variations on this calculation, but after isolating just the Flyweights through Welterweights and filtering only three-round fights to avoid the occasional large cage pay-per-view card with two five-round title fights on the line, the difference is about the same. For just these three-round fights in the similar weight classes, the average duration was almost identical to the numbers shown in the chart. The bigger difference was in five-round fights, where the average fight duration was 16.13 minutes in the large cage and only 13.08 minutes in the small cage – a difference of over three minutes.

Here’s how all the finish rate data breaks down, in one graph:

Does Cage Size Matter - Fightnomics - linesp

The sample in question looked at the most recent UFC events, totaling nearly 800 fights. The majority of them were in a large cage, but 140 UFC fights occurred in the smaller cage since the end of 2012, finally allowing an apples-to-apples comparison within the same promotion. The trend lines are bumpy, as would be expected in a constrained period, but these will likely smooth out over time.

The results show small cage finish rates exceeding the large cage rates for all but two UFC divisions: Flyweight and Light Heavyweight, which admittedly are on the ends of the size spectrum and have smaller sample sizes than the more central divisions. The most populous divisions that saw the most action in the small cage were the Lightweights (33 fights) and the Welterweights (24 fights), and both these divisions show a sizable increase in finish rates above the large cage average.

One of Dana White’s signature declarations is “never leave it in the hands of the judges.” This call to action is paramount to the fight business that sells excitement as a core product. The UFC specifically rewards fighters at each event for exciting performances with explicit bonuses announced at press conferences, which are even tracked as a badge of honor. If these bonuses are ever made into small trophies, they should obviously be nicknamed “Lauzons,” an homage to Joe Lauzon, the leading performance bonus winner in UFC history. With the UFC’s heavy focus on action and exhilaration it is therefore no surprise that the fighters who finish more often are valued the most within the promotion.

So what if I told UFC president Dana White that there was a way to increase the excitement of the UFC’s core product, literally overnight? More finishes for the fans and highlight reels (and future ad promos), more social media flood-inducing OMG moments, and a return the glory days of MMA when the majority of fights ended with strikes or submissions? That one small change could provide more of what fans and promoters want, at virtually no extra cost?

Well, I just did. We’ve accounted for an important variable in finish rate – the size of the fighter – and see a pretty consistent trend. Before sample size is attacked, it was sufficient to confirm statistical significance beyond a reasonable doubt (greater than 95% confidence, or p<0.05). The overall bump from a finish rate of 48% up to 60% (or potentially 62%) is a big deal, and warrants further investigation. What’s causing the increase? These are all the same fighters competing under the same matchmakers and rules, so what is happening when the bell rings that leads to more finishes in the smaller cage?

We have a lot more data to dig through to find out for sure, but we already have a first general answer to the question of whether cage size matters: yes, it does! The small cage may be impacting everything from broadcast times to in-cage sponsor dollars, and even mandatory medical suspensions for fighters and the layoffs that go with them. We’ll consider a few of these in Part 2 of this Cage Size analysis, as well as look at specific fighter performance metrics in each sized Octagon.

Find out more about MMA statistics: “Fightnomics” the book is now available on Amazon!
Follow along on Twitter for the latest UFC stats and MMA analysis, or on Facebook if you prefer.

Raw data was provided by, and in partnership with FightMetric, with additional research by Eli Langbaum, Columbia University.


Be Sociable, Share!
468 ad

One Comment

  1. phil stuart says:

    excellent article thanks,,

    wonder how much more highly profitable, expensive cageside seats you can get round the big octagon as opposed to the small one?


  1. Small Cage Analysis Part 2: the What and the How of the Finisher’s Cage - Fightnomics | Fightnomics - […] Part 1 of the analysis of Cage Size in the UFC we found that finish rates in the smaller Octagon …
  2. Episode 59 - Interview with Reed Kuhn - Hiyaa Martial Arts Podcast - […] Part 1 […]

Leave a Reply to phil stuart Cancel reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>