more specific, such a report might technically be considered valid, but will be of very limited value to the pharmacovigilance department of the company or to drug regulatory authorities. Activities involved in pharmacovigilance 1- Case-control study (Retrospective study). 2- Prospective study (Cohort study). 3- Population statistics. 4- Intensive event report. 5- The spontaneous report in the case is the population of the single case report. Coding of adverse events Adverse event coding is the process by which information from an AE reporter, called the "verbatim", is coded using standardized terminology from a medical coding dictionary, such as MedDRA (the most commonly used medical coding dictionary). The purpose of medical coding is to convert adverse event information into terminology that can be readily identified and analyzed. For instance, Patient 1 may report that they had experienced "a very bad headache that felt like their head was being hit by a hammer" [Verbatim 1] when taking Drug X. Or, Patient 2 may report that they had experienced a "slight, throbbing headache that occurred daily at about two in the afternoon" [Verbatim 2] while taking Drug Y. Neither Verbatim 1 nor Verbatim 2 will exactly match a code in the MedDRA coding dictionary. However, both quotes describe different manifestations of a headache. As a result, in this example both quotes would be coded as PT Headache (PT = Preferred Term in MedDRA). Seriousness determination Although somewhat intuitive, there are a set of criteria within pharmacovigilance that are used to distinguish a serious adverse event from a non-serious one. An adverse event is considered serious if it meets one or more of the following criteria: results in death, or is life-threatening; requires inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability or incapacity; results in a congenital anomaly (birth defect); or is otherwise "medically significant" (i.e., that it does not meet preceding criteria, but is considered serious because treatment/intervention would be required to prevent one of the preceding criteria.) Aside from death, each of these categories is subject to some interpretation. Life-threatening, as it used in the drug safety world, specifically refers to an adverse event that places the patient at an immediate risk of death, such as cardiac or respiratory arrest. By this definition, events such as myocardial infarction, which would be hypothetically life-threatening, would not be considered life-threatening unless the patient went into cardiac arrest following the MI.