Accuracy in Dry Bone Diagnosis: a Comment on Palaeopathological Methods

The objectives of palaeopathological research include: (i) diagnosis of specific diseases in archaeological human remains; (ii) analysis of the impact of various diseases in human populations through time and space; and (iii) clarification of evolutionary interactions between humans and disease. Basic to all these objectives is the need for accuracy in diagnosing diseases in archaeological human remains. Tests of diagnostic accuracy made during workshops in dry bone diagnosis held during the annual meetings of the Paleopathology Association (PPA) in 1989, 1990, 1991 and 1992 suggest important limitations that need to be considered in the development of methods in palaeopathology. Although the conditions do not approximate those found in most field or laboratory situations, these tests indicate an overall accuracy of 28.6 per cent for specific disease recognition and 42.9 per cent accuracy for correct recognition of the more general categories of disease. The factors in diagnostic accuracy are complex and include the knowledge and experience of the observer. Another factor is the often substantial morphological overlap between different diseases. In the classificatory system used for the workshops there are seven general categories of disease, each of which has recognizable, although often non-specific, hallmarks in dry bone specimens. A differential diagnosis with these seven general possibilities in mind rather than hundreds of specific diseases can be a powerful tool for the palaeopathologist in providing data that are more comparable between observers. This improvement in classificatory agreement has important methodological implications in the development of a data protocol in palaeopathological research. The identification of general disease category is recommended as part of descriptive and diagnostic reports on palaeopathological specimens.