Final answer:
A certain percentage of police-juvenile encounters become formal contacts, where the police take official action such as making an arrest or issuing a citation.
Step-by-step explanation:
In police-juvenile encounters, a certain percentage of them become formal contacts. Formal contacts refer to situations where the police take official action, such as making an arrest or issuing a citation. The exact percentage of police-juvenile encounters that become formal contacts can vary depending on various factors, such as the nature of the encounter and the policies of the police department.