Young people are disproportionately responsible for and victims of violent crime. While overall rates of youth crime have decreased since their peak in the mid-1990s, reducing criminal activity committed by young people and putting them on a better path remains a top priority for policymakers. Some proposed policies, such as lowering the age at which a youth can be charged as an adult, come with substantial individual, social, and economic costs and are not based on scientific evidence concerning brain development and impulse control. Strategies that increase the swiftness and certainty of punishment (thus ensuring predictable, short-term consequences) are likely to deter more crime and be far more cost-effective.