The reliance on test scores to assess the impact of schools on student achievement has increased sharply during the past decade. This increase is reflected in the number of states that employ testing programs to hold schools, teachers and students accountable for improving student achievement. According to annual surveys by the Council for Chief State School Officers (1998), 48 states use statewide tests to assess student performance in different subject areas and 32 states currently use or plan to use test scores to determine whether to grant diplomas. In addition, many educational programs, including charter schools, depend on test scores to demonstrate the success of their programs. In many cases, however, educational leaders employ overly simplistic and, sometimes, misleading methods to summarize changes in test scores.

Educational leaders, institutions and the popular press have employed a variety of methods to summarize change in test scores. Below, I briefly discuss the advantages and disadvantages of three commonly used methods: Change in Percentile Rank, Scale or Raw Score Change, and Percent Change. A separate article (Russell, 2000) describes two alternate approaches for summarizing change and demonstrates how a third method, namely Expected Growth Size, can be used to summarize change for vertically equated norm-referenced tests.