When deciding whether to use age or grade-based norms, the examiner must decide which score is appropriate for his/her purposes. If the purpose is to determine Ability-Achievement Discrepancy, age-based scores are recommended as "best practice." If the purpose is to compare the student's scores with those of peers in the same grade, grade-based scores should be used. We do not recommend one score over another. We provide both sets of scores because some school districts prefer one over the other. It is best practice to discuss decision-making with the examiner's supervisor or school district diagnostic personnel, as districts have their own criteria for what types of scores are appropriate to report.