In law, medicine, and statistics, cause of death is an official determination of the conditions resulting in a human's death, which may be recorded on a death certificate. A cause of death is determined by a medical examiner. In rare cases, an autopsy needs to be performed by a pathologist. The cause of death is a specific disease or injury, in contrast to the manner of death, which is a small number of categories like "natural", "accident", "suicide", and "homicide", each with different legal implications. International Classification of Disease (ICD) codes are often used to record manner and cause of death in a systematic way that makes it easy to compile statistics and more feasible to compare events across jurisdictions. Accuracy concerns A study published in Preventing Chronic Disease found that only one-third of New York City resident physicians reported believing that the present system of documentation was accurate. Half reported the inability to record "what they felt to be the correct cause of death", citing reasons such as technical limitation and instruction to "put something else". Nearly four-fifths reported being unaware that determinations of "probable", "presumed", or "undetermined" could be made, and fewer than three percent reported ever updating a death certificate when conflicting lab results or other new information became available, and cardiovascular disease was indicated as "the most frequent diagnosis inaccurately reported". Causes of death are sometimes disputed by relatives or members of the public, particularly when some degree of uncertainty or ambiguity exists in relation to the cause of death. On occasion, such disputes may result from, or sometimes instigate, a conspiracy theory. Public perception of the relative risk of death by various causes is biased by personal experience and by media coverage. The phrase "hierarchy of death" is sometimes used to describe the factors that cause some deaths to get more attention than others. Though some opponents of abortion consider it a cause of death, conventionally medical authorities do not confer personhood on fetuses that are not viable outside the womb, and thus abortions are not reported as deaths in these statistics. Aging Health departments discourage listing "old age" as the cause of death because doing so does not benefit public health or medical research. Aging is not a scientifically recognized cause of death; it is currently considered that there is always a more direct cause (although it may be unknown in certain cases and