This monograph is designed for educators who must make decisions about curriculum, instruction, and the training of teachers. Many important educational decisions are made based primarily, if not exclusively, on test scores. This reliance on test scores has evolved for a variety of reasons. This monograph starts with test scores as a given in American education today, not as an endorsement of the emphasis given to test scores, but as a recognition of what has become common practice. The purpose of this monograph is to describe a set of procedures for reanalyzing test data to extract as much useful information as possible for making important educational decisions. The monograph and procedures described in it focus on the reanalysis of currently available test data, not on collecting new test data and initial analysis. The reasons for focusing on the reanalyses of currently available test data are described in the text. In this monograph, the reanalysis of mathematics test data is described as a model for other educators interested in taking full advantage of test data that have already been collected. (PK)