I’ve been working on a program that allows measurement of the performance of MMA fighters over time, without tunable parameters or the need for human judgement. I used it to calculate the current top five fighters in each weight class in the UFC, then looked at how their scores varied over the last year. Tweaking the code took a little longer than expected, so this is actually 2014 and a little bit of 2015 in review as the report ranges from January 1, 2014 to January 19, 2015, ending immediately after UFC Fight Night: McGregor vs. Siver.

The program is based on two different algorithms across five different histories of 1, 2, 4, 8, and 16 years. The results are then evenly weighted to produce a single confidence measure. The closer a score is to 100%, the more confident the model is that a fighter has won frequently against other winners. A score of 0% means the model has no information – a debuting fighter starts at this. The closer a score is to -100%, the more confident the model is that a fighter has lost frequently to other losers.

It’s best to think of these scores as a report card of actual performance, rather than a theoretical ranking of potential performance. A solid contender fighting frequently and consistently winning might outrank a champion who only fights once a year, and you can check out the lightweights for a shining example of this. It’s not about some abstract measure of skill – it’s about who’s winning the most fights against the best opponents right now.

Flyweight

Demetrious “Might Mouse” Johnson ranks head and shoulders above his division with two successful title defenses in June (against Ali Bagautinov at UFC 174) and September (against Chris Cariaso at UFC 178). Joseph Benavidez broke out of the pack to take second with a win over Dustin Ortiz in late November at UFC Fight Night 57, but still has a long way to go. John Dodson defeated John Moraga in June at UFC Fight Night 42, but by the end of the year both were closely matched. Jussier Formiga’s win against Zach Makovsky in August at UFC Fight Night 47 brought him into the top five.

Bamtamweight

This closely matched division has Raphael Assuncao, Renan Barao, Urijah Faber, and TJ Dillashaw all vying for the top spot. TJ Dillashaw catapulted himself into the elite with a win over Renan Barao in May at UFC 173, but needs a win over a strong opponent to really cement his status as champion. Raphael Assuncao had a strong year with wins against against Pedro Munhoz in February at UFC 170 and Bryan Caraway in October at UFC Fight Night 54. Renan Barao stayed in contention after pulling out a must-win fight against Mitch Gagnon in December at UFC Fight Night 58. Urijah Faber is perpetually a contender, but a recent title shot loss to Barao in February at UFC 169 hurts his near term chances. Dominick Cruz got a big bump in September at UFC 178 with a win against Takeya Mizugaki, but recurring knee injury issues will likely keep him out of competition (and the top of the division) in 2015.

Women’s Bantamweight

Alexis Davis and Ronda Rousey were closely matched until Rousey’s victory in July at UFC 175 cemented her at the top of the division. Cat Zigano got a big bump in late September at UFC 178 with a win against Amanda Nunes, and will challenge Rousey for the title in February 2015 at UFC 184. Bethe Correia and Jessica Andrade round out the top five.

Featherweight

Jose Aldo can deservedly call himself the king of this division, but Conor McGregor is climbing fast. McGregor’s ranking was aided by an aggressively paced fight schedule with victories over Diego Brandao, Dustin Poirier, and most recently Dennis Siver all in the last six months. Aldo and McGregor are being positioned for a title fight at UFC 187 in May 2015. Ricardo Lamas defeated Dennis Bermudez via submission in November at UFC 180 and these two fighters fill out spots three and four. Cub Swanson had a big win over Jeremy Stephens in June at UFC Fight Night 44, but is struggling to maintain momentum after a loss to Frankie Edgar later in the year.

Lightweight

The interesting rankings in this division reflect activity (in the case of Donald Cerrone) and lack of it (in the case of champ Anthony Pettis). Cerrone has been on a tear, and his fast paced schedule against strong opponents has led to his ranking skyrocketing. Pettis has been the opposite, with only a single fight in 2014 and his ranking slowly trends downward as a result. The biggest shakeup in the rankings came in August at UFC Fight Night 49 when Rafael dos Anjos knocked out Benson Henderson demonstrating he belongs near the top of the division. Benson Henderson has been on a slow and steady slide since then, erasing all his gains and then some from a major win against Rustam Khabilov at UFC Fight Night 42 in June. Micheal Johnson rounds out the top five.

Welterweight

This division is a bit of a mess, despite it being quite clear who the top three are – Johny Hendricks, Robbie Lawler, and Rory MacDonald. Lawler became champion in December at UFC 181, but ranks just below Hendricks. Rory MacDonald defeated Tarec Saffiedine in October at UFC Fight Night 54 to cement his contender status, but a talked about title shot never materialized. Rick Story defeated Gunnar Nelson in October at UFC Fight Night 53 to rise to number four. Matt Brown has been consistent across 2014 and rounds out fifth.

Middleweight

Weidman defended his title with a win over Lyoto Machida in July at UFC 175, but his injuries and fight delays have led to a somewhat sleepy title picture in 2014. Ronaldo “Jacare” Souza was a strong contender after defeating Francis Carmont in February at UFC Fight Night 36, but his ranking has steadily slipped since then and is now sitting in fourth. A planned bout with second place Yoel Romero has been delayed, and the winner of this will likely fight for the title. Thales Leites’ biggest win of the year was against Francis Carmont in August at UFC Fight Night 49, pushing him to third, while Tim Boetsch rounds out the top five.

Light Heavyweight

No debate here, Jon Jones is the clear champion at 205 after a decision win over Daniel Cormier at the start of the new year. The real question is who’s up next for the title. Ryan Bader’s victory over Ovince St-Preux in August at UFC Fight Night 47 pushed him into second place, while Phil Davis defeated Glover Teixeira in October at UFC 179 to take third. Anthony Johnson had a strong return to the UFC with a victory over Phil Davis in April at UFC 172, and only his lack of UFC activity in 2012-2013 prevents him from being ranked higher than fourth. Ovince St-Preux bounced back after his loss to Ryan Bader with a win over Mauricio “Shogun” Rua in November at UFC Fight Night 56 to retain his status in the top five.

Heavyweight

Probably the most egregious example of an inactive champion, Cain Velasquez hasn’t fought since October 2013 when he defeated Junior dos Santos for the second time at UFC 166, and his ranking has been on a steady slide for all of 2014. Junior dos Santos picked up a win against Stipe Miocic to rise to first in the rankings in December at UFC on Fox 13, but after two brutal losses to Velasquez his future in the division is unclear. Fabricio Werdum snagged a critical win against Travis Browne in April at UFC on Fox 11, then defeated Mark Hunt in November at UFC 180 to win the interim heavyweight championship. Werdum and Velasquez are tentatively scheduled to meet in June 2015 at UFC 188. Travis Browne defeated Brendan Schuab in December at UFC 181, and Matt Mitrione defeated Gabriel Gonzaga in December at UFC on Fox 13 – both are hungry for their shot but are a fight or two away from the title.

Caveats

The model is strongly sensitive to activity – the more frequently someone fights (and more importantly, wins) the higher they will rank in general. If a fighter hasn’t fought in the last year, they automatically lose 20% of of their total score as two out of the ten scores will be zero (the one year periods). It also only uses UFC and Pride fight data, which leads to certain active fighters with strong careers in other organizations being underrated and not being considered for the top five, like Luke Rockhold at middleweight. Adding in fight data from other organizations is definitely on my to-do list.