Predicting Rafael dos Anjos vs. Donald Cerrone with Pythagorean Expectation

In this weekend’s UFC on Fox 17 main event, lightweight champion Rafael Dos Anjos will look to defend his title against Donald Cerrone. It is a relatively close match up as the odds currently have Dos Anjos as a -200 favorite. has been publishing Fight Forecast for upcoming UFC events for the last few weeks. Fight Forecast features the fighter's career StrikeScore as well as UFC Fantasy predictions, betting odds, Kountermove prices, DraftKings prices and Fight Matrix rankings. 

After four events, career StrikeScore has correctly predicted the winner in 64 percent of bouts, despite only measuring striking efficiency (read about it here). The only other model to perform better over that stretch was the DraftKings prices, which have picked correctly in 66 percent of bouts.

For this main event, we are going to apply Pythagorean Expectations to the StrikeScore model. Career StrikeScore takes into account all strikes thrown and landed by a fighter and his/her opponent over the course of their career. PythagScore will look at each fight individually and give an estimate of how many fights a fighter “should” have won given their StrikeScore. This estimate should provide a more accurate representation of a fighter’s skill and accomplishment as a striker.

Pythagorean Expectation is a formula developed by Bill James. The idea is to compare a baseball team’s actual winning percentage with their Pythagorean winning percentage. If there is a great variance between the two, than the team was either extremely lucky or unlucky. The same can be applied to MMA. If a fighter has lower PythagScore than their winning percentage, it is possible they were getting gift decisions or just plain lucky. The basic formula is below.

from Wikipedia

from Wikipedia

The formula has been adapted for use in other sports by using a different exponent. Once a larger sample of data has been culled, StrikeScoreMMA will likely also adjust the exponent as well.

The following charts show the StrikeScore for all of Dos Anjos’ and Cerrone’s fights in the Fightmetric database.

After running the numbers through the formula, Dos Anjos has a 97 PythagScore while Cerrone’s score comes in at 57. The new measure picks the same favorite as career StrikeScore (Dos Anjos 166 to Cerrone 125). However, PythagScore has Dos Anjos as a much bigger favorite.