Dodge

Dodge is a champion statistic that gives the champion a chance in terms of percentage to completely avoid an autoattack from an aggressor. Dodge is in the process of being phased out in order to simplify champion statistics.

Calculations
The dodge formula is a multiplicatively cumulative formula. By default, each champion has a dodge modifier of 100, meaning they will be hit by every physical attack directed at them. Sources that modify the dodge stat are multiplied in sequence, reducing the previous dodge modifier by the given percentage.

This means that each increase in the dodge chance has less of an impact on the total dodge modifier. If a champion wears an item that increases dodge chance by 10%, their dodge modifier will be 90% of 100, or 90 (10% of physical attacks are dodged). If the champion buys a second such item, their dodge modifier will be 90% of 90, or 81 (19% of attacks are dodged), not 80% of 100.

However, this does not mean dodge has diminishing returns - it scales linearly. Each source of dodge is as good as the last. This is because while you are getting less percentage dodge chance, each percentage you dodge is better. For an extreme example, consider the change from 98% to 99% dodge. This literally doubles your protection even though it is only a 1% change.

In short the formula is: 1 - ((1-a)(1-b)(1-c)....(1-n)) Where the variables a, b, c, and n are the dodge % values and are converted to their respective decimal values.

In calculating the dodge modifier, dodge chance from all runes are added together and treated as one source, with every mastery, champion ability, and individual items treated as an different additional sources after that.

Currently, the highest possible dodge chance in the game can be acquired by with maximum ranked  (18%), 9 Tier 3 Seals of Evasion and 3 Quints of Evasion (11.25%), and 6 Ninja Tabi equipped (6 sources, 12% each), giving him a final dodge of approximately 66.2%.

Calculation for above:

1 - (1 - .18) * (1 - .1125) * (1 - .12)^6 = .66202

100 * .66202 = 66.2% since we rounded .66202 to .662

This value is the % of auto attacks dodged. In order to find out what % of auto attacks hit:

100% - 69.71% = 30.29%

It is also worthy to note that the game mechanics first calculates if you dodged the attack or not; then, if the attack did land, it will calculate if attack is a critical hit or not. In other words, the critial hit chance is the % chance of a critial on attacks that land and is not affected directly by the dodge %.

Items

 * The item gives the holder 12% dodge, 25 armor, and enhanced movement
 * suck ass balls bitches

Champion abilities

 * increases his dodge chance by 10/12/14/16/18%.
 * increases his dodge chance by 3% for 5 seconds upon switches stances (stackable up to 3 times).

Runes

 * runes increase dodge chance.

Dodge Removal
Riot announced that they will remove dodge.