The theory behind PMT has been "repeatedly validated", and many programs have met the "gold-standard criteria for well-established interventions".  All of the established programs teach better parenting skills and emphasize that the parent-child relationship is "bidirectional".Specific treatment programs that can be broadly characterized as PMT include parent–child interaction therapy (PCIT), the Incredible Years parent training (IYPT), positive parenting program (Triple P), and Parent management training – Oregon model (PMTO). PCIT, IYPT, Triple P and Helping the non-compliant child (HNC) are among the most frequently used PMTs; according to Menting et al (2013), IYPT "is considered a 'blueprint' for violence prevention".The per family cost of group parent training programs to bring an average child into a non-clinical range of behavioral disruption was estimated in 2013 to be US$2,500, which according to the authors of a Cochrane review was "modest when compared with the long-term health, social, educational and legal costs associated with childhood conduct problems".