As you may know, the Elo system is a popular rating instrument used in the world of chess. In the combat sports world, it has inspired the widely known boxing ratings over at BoxRec and to a lesser degree, the standard system used here. From a broader standpoint, as far as I know, it is considered the grandfather of mathematical-based rating systems.
Now, it does have its flaws and those flaws were on display for many years over at site called MMA Elo, but those issues were compounded by the lackluster data efforts by that site’s creator — a problem you won’t see here.
At its core, Elo is simple math. That’s what makes it so interesting. It is very simple, but does offer a few variables that can be optimized for the specific task at hand, most notably, the K-factor. Simply put, the K-factor affects the amount of change that a single contest can have — the lower the K-factor, the smaller the potential change and vice-versa.
In chess, a sport that often has a frequent, consistent and logical schedule, the K-factor is quite low, commonly between 16 and 32. It turns out, a K-factor somewhere between 150 and 200 yields the most accurate prediction rates in MMA.
So, to start, the Elo system will be implemented with a starter rating of 1000 and a K-factor in the neighborhood of 170. There will be no provisional system and no K-factor tiers (yet), but the plan is to offer a few flavors and perhaps incorporate some other common systems as well. These flavors will be entirely driven by prediction rates in some shape or form and there will be no emphasis on subjectivity, so things could get a little wacky.
The “standard” system you’ve seen for over a decade will still be the default, but we’ll be giving you the option to filter the divisional pages by system. The one thing to keep in mind, is that the Top X fighters displayed will (at least for now) be driven by the standard system only — which means that the #251 Heavyweight by our standard measure, may be the #249 Heavyweight by Elo, but since he didn’t make the standard cut, he won’t be in the lists. This may or may not change in the future.
Any and all comments are welcome.