This digest explains basic elements of standardized tests in order to help teachers in making students feel comfortable about taking such tests. Usually created by commercial publishers, standardized tests are designed to provide a common measure of students' performance. They help compare an individual student's performance with the performance of a group of students from a given class, school, or school system. They also help compare students' performance across the country. Standardized achievement and aptitude tests are described, and their limitations are discussed. Means of helping students prepare for testing are outlined, and pointers for helping students assess the testing experience following the test and after receiving the test results are provided. A list of additional literature resources is included. (TJH)