Kill to Death ratio (often referred to as KDR) is simply the number of kills one has, divided by the number of deaths. League of Legends does not explicitly track this information, but it can easily be calculated manually. A more modern variant of this ratio is the KDA, or Kill Death Assist (Ratio), which also calculates Assists.
For DPS champions, such as Assassins or Carries, it is often seen as one of the most effective ways to evaluate a player's performance. Players with these types of characters should be achieving a KDR greater than 1. In addition, new and lesser informed players generally believe that higher KDR indicate better players.
Other types of champions, such as Pushers, Tanks, and Support characters do not emphasize a high KDR as a factor of a successful game, but take other factors into consideration. Supports and Tanks should have many more assists, and minimal deaths. Pushers should be evaluated by the amount of towers they've pushed down.
In a game, comparing the KDR of both teams as a whole is useful as a very rough guide of how well both teams are doing. A comparison of KDR will not give a good approximation of a team's total gold. This means that a team can have more gold than the other team but still be behind in total kills. Capturing objectives that grant gold to an entire team such as destroying turrets or defeating large jungle creeps not only provides much more total gold to the team, but it also gives map control, which can leave other objectives vulnerable and easier to capture.
A player may be described as having a "negative" KDR. This is a misnomer and simply means that the player's KDR is less than 1.
- If Player 1 scores a 6:2:5, the K/D-Ratio is 6 / 2 = 3.0.
- If Player 2 scores a 2:6:8, the K/D-Ratio is 2 / 6 = 0.33.
- If Player 3 scores a 4:2:17, the K/D-Ratio is 4 / 2 = 2.0.
Keep in mind that assists play an important role that can not be seen by just calculating the K/D-Ratio. That is why the KDA (Kills / Deaths / Assists) ratio is used more in tournaments to display teamwork and skill. For example, Player 3 (10.5) has a higher KDA ratio than Player 1 (5.5) and helped the team more even though Player 1 has a higher KD ratio.
Another type of scoring is dominance factor (DF), shows even more domination is simple. Kills count as 2, deaths count as -3, and assists are 1. This may seem slightly confusing at first but let's look at the examples from above.
- If Player 1 scores a 6:2:5, the DF would be 11.
- If Player 2 scores a 2:6:8, the DF would be -6.
- If Player 3 scores a 4:2:17. the DF would be 19.
As you can see this accounts all aspects and can give you a more accurate reading. This also gives more opportunity to those who play supports.