of investigation, require further analysis using all available data in an attempt to confirm or refute the signal. If the analysis is inconclusive, additional data may be needed such as a post-marketing observational trial. Signal detection is an essential part of drug use and safety surveillance. Ideally, the goal of signal detection is to identify adverse drug reactions that were previously considered unexpected and to be able to provide guidance in the product's labeling as to how to minimize the risk of using the drug in a given patient population. Risk management plans A risk management plan is a documented plan that describes the risks (adverse drug reactions and potential adverse reactions) associated with the use of a drug and how they are being handled (warning on drug label or on packet inserts of possible side effects which if observed should cause the patient to inform/see his physician and/or pharmacist and/or the manufacturer of the drug and/or the FDA, European Medicines Agency. The overall goal of a risk management plan is to assure a positive risk-benefit profile once the drug is (has been) marketed. The document is required to be submitted, in a specified format, with all new market authorization requests within the European Union (EU). Although not necessarily required, risk management plans may also be submitted in countries outside the EU. The risks described in a risk management plan fall into one of three categories: identified risks, potential risks, and unknown risks. Also described within a risk management plan are the measures that the Market Authorization Holder, usually a pharmaceutical company, will undertake to minimize the risks associated with the use of the drug. These measures are usually focused on the product's labeling and healthcare professionals. Indeed, the risks that are documented in a pre-authorization risk management plan will inevitably become part of the product's post-marketing labeling. Since a drug, once authorized, may be used in ways not originally studied in clinical trials, this potential "off-label use", and its associated risks, is also described within the risk management plan. Risk management plans can be very lengthy documents, running in some cases hundreds of pages and, in rare instances, up to a thousand pages long. In the US, under certain circumstances, the FDA may require a company to submit a document called a Risk Evaluation and Mitigation Strategy (REMS) for a drug that has a specific risk that FDA believes