There is a difference between a child who has runaway and child that is missing. A runaway has left home or left a supervised environment. They usually run to escape or avoid something, or they are running somewhere to find or get something. A missing child might be lost, abducted, injured or held against their will by others.
Motivations of a runaway:

• To avoid an emotional experience or consequence that they are expecting in some future encounter or situation.
• To escape a recurrent or ongoing unpleasant, painful or difficult experience in their life.
• To avoid the loss of activities, relationships or friendships that are considered important or worthwhile.
• To change or stop what they are doing or about to do.

The following is a brief list of suggestions that can help reduce the risk of a runaway. Communication That Helps Prevent Runaways:

• Never use sarcasm or a negative attitude that demonstrates that you do not respect your child
• Never raise your voice or yell - especially when child is doing that.
• Stay calm and quiet, make eye contact, and don't respond if your child is angry, shouting or in a rage. Wait until the child is calm.
• Never interrupt your child when he is talking or trying to explain something - even if you disagree. Wait until he finishes his talk.

Keep in mind that these are only suggestions. If the risk is high, and your relationship is extremely poor, including the level of trust, then these suggestions may not help. Obtain the support and advice of a qualified profession if you feel there is a risk that your child may run away.