MST is a family and home, evidenced based treatment that strives to change how youth function in their natural settings-home, school, and neighborhood-in ways that promote positive social behavior while decreasing antisocial behavior. The primary goals of MST are to: (a) reduce youth criminal activity; (b) reduce other types of antisocial behavior such as drug abuse; and (c) achieve these outcomes at a cost savings by decreasing rates of incarceration and out-of-home placement.