Skilled teachers who assess students using high quality, relevant and timely assessments can use the results to modify, refine and individualize instruction. Student assessments should be a reflection of what is taught in the classroom. As more accountability provisions have been implemented at the national, state and district levels, the focus on test scores and their implications has dictated what students should learn. Although the federal government requires testing in most grades, these requirements are often supplemented at the state and district levels. This results in increased testing and test preparation without providing additional information to help teachers inform instruction and understand their students' academic standing and needs. The American Federation of Teachers (AFT) believes it is critical to define and describe appropriate testing practices, to advocate on behalf of teachers and their students for sound assessment policies, and to align standards and curricula at each grade level. It is imperative that states, districts and teachers understand the purpose of various types of tests and test results. In some cases, new tests that yield more useful results may need to be developed. To help create a common language and understanding of what is appropriate, this article defines the most commonly used tests and provides recommendations about how these tests should be used. A list of commonly used tests is included in the Appendix.