RQ‐MODE PRINCIPAL COMPONENTS ANALYSIS OF CERAMIC COMPOSITIONAL DATA*

Abstract

RQ‐mode principal components analysis (PCA) is a means for calculating variable and object loadings on the same axes, so that elements can be displayed along with data points on a single diagram. The biplots resulting from RQ‐mode PCA preserve both Euclidean relations among the objects and variance‐covariance structure. When used with data on the chemical composition of archaeological pottery, such biplots facilitate recognizing compositional subgroups and determining the chemical basis of group separation. RQ‐mode PCA is illustrated in this paper with neutron activation data on Mesoamerican Plumbate pottery.