Standardized achievement tests try to assess the knowledge and skill base of those taking tests in particular content areas, such as mathematics or language arts. The standardized tests originally were created to inform teachers and parents about students' achievements relative to their peers, to assist in placing students in appropriate programs and to justify the allocation of certain sources of funding. Standardized testing allows for more accurate comparisons than differentiated testing; theoretically, differences in the number of correct answers are due to differences in skills, aptitudes or knowledge bases and not differences in the tests themselves.
Standardized achievement tests are used in the 21st century in ways not originally intended, which has caused much debate. While they are still used to help allocate funding, school boards, educators and parents now rely on these exams to evaluate a school's effectiveness and teachers' performances. The No Child Left Behind Act also relies on standardized tests to evaluate schools' performances, which can influence funding allotments. The theory is that students' results on these tests are reflections of their teachers' effectiveness and the quality of their educational programs generally.
Standardized achievement test results are given in percentiles--not percentages--meaning scores are comparisons of how students did in relation to all other students in their demographics. For instance, a fourth-grade student who tests in the 98th percentile in the science section of a standardized test answered the same number or more questions correctly on that section than 98 percent of her peers.
Educators are sharply divided over the efficacy, accuracy and usefulness of standardized achievement tests. On the one hand, these exams can provide valuable information on how one student performs in relation to other students in his demographic, conveying valuable information on students' strengths, weaknesses and how to create better academic programs.
On the other hand, W. James Popham, former president of the American Educational Research Association and professor emeritus at the University of California, Los Angeles, School of Education and Information Studies, contends that use of standardized tests to measure the quality of schools has been a mistake for decades: "That's because the standardized tests employed are flat-out wrong." According to Popham, standardized tests now used result in limited curriculum, excessive drilling and teacher dishonesty and should be replaced with "instructionally supportive" accountability tests.
In the United States, five main standardized achievement tests are used to evaluate schools' levels of effectiveness: the California Achievement Tests, Comprehensive Tests of Basic Skills, Iowa Tests of Basic Skills, Metropolitan Achievement Tests and Stanford Achievement Tests.