The methods and techniques used in Categories 1, 2, and 3 are the least reliable because of their subjective nature as well as the ever-present potential for human error. These methods are valuable, however, as adjuncts in identification procedures in a total exclusionary and inclusionary comparison. The methods and techniques described in Category 4 have a more scientific basis, but still caution must be used, and, prior to the completion of the death certificate, a complete evaluation should be made of all techniques employed in the identification.