Grade Equivalents: Accuracy and Certainty of Interpretations Among Parents, Teachers, and School Psychologists

Scores on standardized tests (e.g., Iowa Test of Basic Skills, Wechsler Intelligence Scale for Children III, Wechsler Individual Achievement Test) can be represented by a number of different metrics. One of the ways scores can be represented is with grade equivalents, which tend to be popular with parents and teachers because they seem to be fairly easy to understand. However, several researchers have claimed that grade equivalents are often misinterpreted. Standard scores are viewed by many researchers as the superior type of derived score. However, standardized scores can be difficult to understand, particularly for individuals with little or no training in statistics (e.g., parents, teachers). Thus, grade equivalents are still widely used. Because grade equivalents are used for determining abilities, assessing learning disabilities, and identifying gifted children, it is important to know if they are misinterpreted. The purpose of the current study was to examine the extent to which teachers, school psychologists, and parents misinterpret grade equivalents. The participants included 39 school psychologists, 32 elementary school teachers, and 30 parents. All participants completed a questionnaire that included demographic information (e.g., gender, career) and several items designed to assess their understanding of the meaning and properties of grade equivalents. Participants were instructed to rank the certainty of their responses on a five-point Likert scale. Although grade equivalents were designed to make standardized test results more meaningful, I found that substantial proportions of parents (76.7%), teachers (67.7%), and even school psychologists (41%) made inaccurate interpretations. In addition, I found that even when people misinterpreted grade equivalents, they generally were as certain of their interpretations as those who accurately interpreted them. Furthermore, in many cases, the people who misinterpreted grade equivalents were certain that they were correct in their interpretations. The results of this study support the notion that grade equivalents are often misinterpreted and should not be used to interpret test scores