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5/25/11 3:04 PM - Rambling Article of the Day: Home/Away Win%

Being involved (prior to Fight Matrix) in the rating system at BoxRec, I discovered many of the factors that prove to be advantages (or disadvantages) to fighters.  One of them was the advantage of fighting on home soil.  This seems pretty obvious, but the advantage was MASSIVE, much larger than you’d expect.  Due to the maturity and availability of data at BoxRec, we were able to determine that this advantage was more directly correlated with a promoter advantage as nationality isn’t always “cut and dry”, case in point, the many eastern European fighters making their money in Germany.

In the end, we decided not to implement this into the rating system as it did have some difficulties; some boxing cards have multiple promoters and fans would find it strange that this influence was factored out of the ratings.  Anyway, from the start of Fight Matrix we have collected nationality data and most recently, I have routines that give a “best guess” as to where a fight took place.  I wanted to look at data regarding American fighters, as it was the most plentiful.  Anyway, here we go:

By the way, be prepared to be surprised.

Scenario Win%
US fighter vs. non-US opponent in US 43.3%
US fighter vs. non-US opponent in non-US 47.6%

Fights in years 2000-2011.  Draws and no contests excluded.  Fights and fighters with incomplete data are excluded.

So at this point, I’ve checked my data  and data query a few times, they’re both legit.  How do we explain this?  Is the average American who fights outside of the country “better” than those that stay here?  Are non-American fighters simply better, on average?  This is way different than in boxing, where there is much more money being tossed around (foreign countries can afford to fly in American fighters with glossy records).


Scenario Win%
US fighter vs. CA fighter in US 43.9%
US fighter vs. CA fighter in Canada 44.4%

Fights in years 2000-2011.  Draws and no contests excluded.  Fights and fighters with incomplete data are excluded.

Have skill, will travel?  I just don’t know what to make of these results.  I think we have to assume that it’s essentially a universal concept in MMA that fighters who are at or above a certain skill level will travel outside of their domain to make money, therefore, they are pushing the “away” win percentages up above the “home”.  The domestic fighters who stay at home, are doing the opposite.


Let’s take a look at one last group — the Japanese fights leaving Japan in the last five years, as it seems that they have suffered much less success than they did in Japan.  Here, we’ll take a look at all their fights, regardless of who it was against.


Scenario Win%
JP fighter in Japan 50.0%
JP fighter in US 39.0%

Fights in years 2006-2011.  Draws and no contests excluded.  Fights and fighters with incomplete data are excluded.

So here, I start to see what I expect.   There are SO many Japan vs Japan match-ups, the “home” percentage was practically glued to 50%, but look at the huge drop in winning percentage!


Let’s roll back and perform this analysis with US fighters, and also use multiple timespans to see if that makes a difference.


Scenario ’00-’05 Win% ’06-’09 Win% ’10-’11 Win%
US fighter in US 49.8% 49.7% 49.6%
US fighter in non-US 47.8% 49.0% 47.8%

Draws and no contests excluded.  Fights and fighters with incomplete data are excluded.

OK, so what did we learn?

  • Most MMA fighters travel for a reason, because they are the most skilled in their respective countries.
  • Japanese fighters do not fit this mold.  Either because they wait until their post-prime years to leave, or perhaps it is due to the chronic weight draining issues that we do NOT see in Japan.   Determining this would take further analysis.

This post took a different direction as my results weren’t what I expected.  Perhaps when I get time, I will use the point system to see exactly how much this comes into play there.