Queue dodging

Queue dodging is the act of leaving the champion select screen by shutting down the connection with the server. It is an act that is frowned upon and penalized by the system. There are various reasons why people queue dodge, generally because they aren't content with the champion selection.

Sometimes queue dodging isn't intentional, but just the result of a connection loss, computer crash or other event.

Methods
The most common and easiest method to queue dodge is by just quitting the client. This is done using the 'X'-button in the top right corner.

Other methods include disabling the connection with the internet, removing power from your computer... These are more drastic measures that might damage your computer. It's not advised to do these.

Penalties
Penalties for queue dodging vary according to the game type. Penalties for leaving ranked champion select are generally greater than those for leaving normal. (source?)

Normal penalties
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Ranked penalties
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Reasons
The primary reason why people queue dodge is because of the selected champions. They might not feel playing against a certain champion or team composition or the other way around: they have the feeling that the team or champion they are forcedto play with won't be good enough to secure a victory.

Also one might have the desire to play with an already selected champion. This is often the case when a new champion is released or in free week and many people want to try him out. This might result in a vicious circle. Someone picks this champion first causing another person to leave. The game is disbanded and the same happens again in the next game. This might go on for some time, causing long times before people can actually play.

Another reason why one might leave is an external factor. Besides the obvious technical problems (connection loss, computer crash...) that causes a queue dodge, there might be reasons like: friends came online while this person is in champion select and he decided it was worth it to receive a penalty in order to be able to play with them. Others include being unexpectedly called away from the computer and others..

How to avoid
Before you start searching for a game, ensure that you have enough time to complete the game. Also check the stability of your system in order to prevent errors, crashes and other problems. You might want to close other applications to reduce the risk of this happening.

Furthermore, talk enough during champion select so that others know what you'd like in this game. Try to build a positive environment that everyone is comfortable with. Give people a chance when they select unusual strategies. For example, ability power Tristana might be a viable build. When you queue dodge you lose ranked rating anyway, so it's better to try to play the game. You might win.