Standardized achievement tests may not be an accurate diagnostic tool for measuring individual pupil achievement in reading. Criterion-referenced tests, designed to measure specific goal mastery, can provide valuable information that standardized forms cannot. In addition, criterion-referenced tests give teachers the diagnostic tools needed to individualize instruction and increase instructor effectiveness in educational decision-making. Caution must be exercised to ensure that testing reflects the instructional emphases of the school's reading program, and that objectives are written at an appropriate level of specificity. Issues of teacher support, test reliability, and integration of separate skills with sustained reading must also be considered. (KS)