ABSTRACT
Tests differ in several respects, the most important differences being intended purpose, manner of reporting scores, and format. Achievement tests try to measure what the child has learned in the past. Large-scale achievement tests attempt a similar goal on a regional or national basis. Examples are the Metropolitan Achievement Test, the Iowa Test of Basic Skills, and half a dozen other well-known "instruments"—a word that publishers prefer to "tests," perhaps because it connotes more precision. Minimum competency tests further confuse the distinction between achievement and aptitude. In reality, they can be either one or both. Criterion-referenced tests try to avoid the problems inherent in percentiles and grade equivalents. Instead of comparing children to their grade-mates, criterion referencing compares each student's achievement to some fixed standard, or criterion. A student simply passes or fails each section of the test according to how many items he or she answers correctly.
