A prescription drug monitoring program (PDMP) involves a specified procedure for addressing prescription drug diversion and abuse. PDMPs have a number of components that have different functions, including patient care, a drug epidemic early warning system, and conducting investigations of drug diversion and insurance fraud. PDMPs can help drug prescribers avoid drug interactions and identify drug-seeking behaviors or "doctor shopping." PDMPs can also be used by professional licensing boards to identify clinicians who evidence patterns of inappropriate prescribing and dispensing, as well as to assist law enforcement in cases of controlled substance diversion. PDMPs also ensure patient privacy, since law enforcement personnel cannot access patient-specific PDMP data unless they have an active investigation; and healthcare providers can access only the PDMP data relevant to their patients. Regarding the effectiveness of PDMPs in countering prescription drug abuse, a 2010 study found that when PDMP data were used in an emergency room, 41 percent of cases had altered prescribing opioid pain medications after the clinician reviewed PDMP data. A 2002 report by the U.S. General Accountability Office found that Kentucky, Nevada, and Utah reported that PDMPs reduced the unwarranted prescribing and subsequent diversion of abused prescription drugs in their States. Currently, 35 States have operational PDMPs, and 11 additional States and 1 U.S. territory have passed legislation that authorizes the development of a PDMP. Because not all States have a PDMP and data sharing and interoperability between States has not been implemented, the full benefit of PDMPs has not been realized. The Office of National Drug Control Policy is working with Federal, State, and nongovernmental partners in supporting the development of operational PDMPs in every State. 1 table