Proportional reporting ratio: The proportional reporting ratio (PRR) is a statistic that is used to summarize the extent to which a particular adverse event is reported for individuals taking a specific drug, compared to the frequency at which the same adverse event is reported for patients taking some other drug (or who are taking any drug in a specified class of drugs). The PRR will typically be calculated using a surveillance database in which reports of adverse events from a variety of drugs are recorded.U.S.-Mexico Border Infectious Disease Surveillance Project: The U.S.Postmarketing surveillance: Postmarketing surveillance (PMS) (also post market surveillance) is the practice of monitoring the safety of a pharmaceutical drug or medical device after it has been released on the market and is an important part of the science of pharmacovigilance. Since drugs are approved on the basis of clinical trials, which involve relatively small numbers of people who have been selected for this purpose - meaning that they normally do not have other medical conditions which may exist in the general population - postmarketing surveillance can further refine, or confirm or deny, the safety of a drug after it is used in the general population by large numbers of people who have a wide variety of medical conditions.National Outbreak Reporting System: ==The National Outbreak Reporting System (NORS)==Notifiable disease: A notifiable disease is any disease that is required by law to be reported to government authorities. The collation of information allows the authorities to monitor the disease, and provides early warning of possible outbreaks.