England's Home Office says anger management training makes violent offenders better at managing their anger. It also appears to make them better at violent offenses:
Anger management courses for convicted armed robbers, wife beaters and stalkers are being axed by the prison and probation services following an official inquiry into the murder of the city financier John Monckton. Home Office instructions sent to the probation service say that anger management courses are counterproductive and actually help violent offenders who make premeditated attacks to manipulate the situation to their advantage.
[Via Rational Review.]