Some multivariate displays for NAEP results

The principal goal of graphic display is to ease access to complex information. Simple univariate displays are easy to understand but usually do not have the capability to transmit accurately the often complex structure of multivariate data. Multivariate displays were specially designed for exactly this purpose. The National Assessment of Educational Progress (NAEP) generates data of a multivariate richness and complexity that defies accurate univariate transmission. The broad use and understanding of the information NAEP provides can be aided through the use of more suitable and evocative data displays. In this article, we demonstrate the limitations of univariate displays and suggest some multivariate displays that may enable us to understand, and thence communicate, what is contained in NAEP more fully.