The pathologist must base his/her opinions on concrete data derived from such practices as determination of the precise location of any bullet wound, microscopic studies of the wound, X-ray and fluoroscopic examination of the direction of a bullet through the body, and exact measurements of the length and depth of each wound. Standards used by pathologists to interpret data are objective and reliable in some cases, notably fingerprint identification and interpretive standards for identifying electrical burns. Under the microscope, the epidermis in a typical electric burn will be evaluated. Interpretive standards for other determinations, however, have their limitations. Age estimates from adult skeletal examinations are accurate only in a plus or minus 5-year range. Determining the age of a bruise is difficult because there is considerable individual variation in the way the skin reacts to injury. Similarly, not very much weight should be attached to a pathologist's description of a stabbing weapon if the opinion is based solely on wound dimensions. The stabbing compresses tissue and may produce a track wider and longer than the knife blade. Determining death by drowning is also difficult. The presence of diatoms do not constitute positive proof of drowning. Further, it is questionable whether an exact time-of-death determination can be made based on body heat loss. Not infrequently it is the pathologist who correlates the autopsy findings with multiple injuries and substantiates the diagnosis of child abuse. An example of a postmortem report is appended. (Publisher summary modified)