Evaluating consistency in typology and classification

Typological systems are essential for communication between anthropologists as well as for interpretive purposes. For both communication and interpretation, it is important to know that different individuals using the same typology classify artifacts in similar ways, but the consistency with which typologies are used is rarely evaluated or explicitly tested. There are theoretical, practical, and cultural reasons for this failure. Disagreements among archaeologists using the same typology may originate in the typology itself (i.e., imprecise type definitions, confusing structure) or in the classification process, because of observer errors, differences in perception and interpretation, and biases. We review previous attempts to evaluate consistency in typology and classification, and use consensus analysis to examine one well-established typology. Both consensus and disparity are apparent among the typologists in our case study, and this allows us to explore the kinds of forces that shape agreement and diversity in the use of all typological systems. We argue that issues of typological consistency are theoretically and methodologically important. Typological consistency can be explicitly tested, and must be if we hope to use typologies confidently.