Positive Behavior Support (PBS) and School-Wide Positive Behavioral Interventions and Supports (SWPBIS) have been researched for decades, with hundreds of research articles showing the efficacy of both.
Research may be accessed at these websites:
The PBIS National Technical Assistance Center
The Journal of Positive Behavior Interventions
Research articles on Positive Behavior Support:
Research articles on School-wide Positive Behavioral Interventions and Supports: