League of Legends has over 160 champions, a multitude of items and runes, as well as a number of effects and other features that need to be balanced, almost religiously, every 15 days, an interval in which patches arrive at MOB.

This is definitely not an easy mission for Riot Games employees and the process generates a lot of curiosity in the community.
In this way, Matt Leung-Harrison, leader of the balancing team, revealed all about the grand task to balance LOL.

The behind-the-scenes lol balancing: What is behind the patch notes?

In an interview with Podcast oken by Concept, Horizon stated that the balancing team contains 10 to 20 people.
We support ourselves a lot in data, as you can imagine. I am one of the people who most support data use, because informal evidence is complicated and prone to personal bias.
The designer also stated that the balancing team is aware of several topics, being one of the main fact that the game needs to be balanced for four different audiences:
Median player: is the audience that goes from 0 to 90%, equivalent to the players of iron to gold i
Skillful players: It is the audience that goes from 90% to 99.5%, equivalent to the gold players I to the day I
Elite: equivalent to links above diamond i
Pro Players
To balance LOL to four quite different audiences, the team analyzes everything that is strong or weak in all these hearings.
If something is not strong in any of these classifications, then we snort it, but if something is strong in any classification, then lets nervous it.
Other metrics that the team uses for balancing are: victory rate, banishment rate and even mastery.
Something quite interesting is that some people involved in balancing are called owners of the position.
It is difficult to understand the balance of an entire game, and it would be too much to ask for only a person to be a specialist in all positions, so there are small groups of employees focused on each function of the game: top, hunter, middle, shooter and support. All these people need to be at least in the diamond link and many are even masters.
Horizon also assured that LOL is not balanced according to the exclusive data of major servers, i.e. the goal of regions such as China and South Korea is not privileged compared to others.

Still, the team follows trends from other places, such as the fact that some champions, such as Yahoo or Yuri, are less hated in some servers and regions than in others.
In addition, the balancing team has some principles, which were adopted as lessons were learned, such as not making many new changes at once.