Using statistical literacy skills to determine appropriate scales to be used on graphs is an essential part of numeracy. Using several meaningful contexts, this article explains very clearly when it is appropriate and inappropriate to begin the scale of a graph at zero.

When the Educational Testing Service became the administrator of the National Assessment of Educational Progress (NAEP) in 1983, it introduced scales based on item response theory (IRT) as a way of presenting results of the assessment to the general public. Some properties of the scales and their uses are discussed. Initial attempts at presenting…

A new approach to the quantification and interpretation of change when only repeated cross-sectional data are available--the Trajectory Analysis of Matched Percentiles--is presented. A recent attempt to interpret the findings on reading achievement of the National Assessment of Educational Progress is critically analyzed. (SLD)

This paper gives an overview of the methods of moderation, or quality assurance and quality control, as they may be more widely known, that are used to enhance the quality of student assessment. The discussion is based on the educational systems of the United Kingdom but is applicable to assessment in other countries. Quality in assessment is seen…