A Simple Method for Quantifying Compositional Correspondence Between Zooarchaeological Assemblages Using Paired Similarity Indices

Abstract

Archaeologists employ an array of comparative approaches to assess zooarchaeological assemblages and the human behavior that produced them. Similarity indices are a simple and effective method for evaluating correspondence between the taxa present and their abundances in two zooarchaeological assemblages. Yet, these indices are not as widely used as other approaches. Here, I review several similarity metrics and present a method for measuring assemblage similarity using paired incidence- and abundance-based indices. The combined results of these measures can be used to classify a set of assemblages according to their dissimilarity, qualitative similarity, quantitative similarity, or substantive similarity. The paired-index approach is demonstrated employing the corrected Forbes and Morista-Horn indices in two zooarchaeological case studies from the Caribbean sites of Sabazan (Carriacou), Sandy Ground (Anguilla), and Creve Coeur (Martinique) in the Lesser Antilles. I show that the method (1) provides a means to quantify the similarity between assemblages along a defined, meaningful scale; (2) offers a straightforward approach for understanding how the dimensions of assemblage similarity interact based on a proposed classification scheme; and (3) constitutes a simple-to-apply technique requiring minimal technical skills. I conclude by discussing the strengths and limitations of this method and its potential wider application in archaeology.