Several researchers have argued that the functional behavior assessment (FBA) and behavior intervention plan (BIP) mandates in the Individuals With Disabilities Education Act of 2004 have gone beyond the current research base. For instance, although BIPs have been shown to improve student outcomes when implemented with strict control and oversight by researchers, it is unclear whether these relationships hold true when implemented under real educational conditions. The purpose of this research was to conduct an initial study evaluating the relationship among the evidence-based quality of federally mandated BIPs, treatment integrity, and student outcomes under real-world educational conditions free from the help of researchers. Results indicated that the evidence-based quality of BIPs was significantly related to positive student outcomes. Results also supported the role of treatment integrity as a mediator of the relationship between the evidence-based quality of BIPs and student outcomes. The implications and limitations of this research as well as directions for future research are discussed. (Contains 3 figures and 5 tables.)