These tests evaluate a child's abilities in specific school subjects, such as reading, oral language, written language, and math. Intelligence may play a role in completing these tests, but it is not directly measured by achievement tests.
Children with ADHD who score poorly on IQ tests are often quite bright. Achievement tests sometimes suffer from the same problems as IQ tests (e.g., adherence to standardized rules and timed tests). Nonetheless, achievement tests may more accurately reflect the true abilities of children with ADHD. There is a pattern of performance on achievement tests that can be quite helpful in diagnosing ADHD. Scores on tasks that do not require sustained effort are usually high scores, while scores on tasks requiring long-term concentration are low. These tests help sort out problems due to concentration versus a true lack of ability. Links to information about these assessment tools can be found in the Resource List.
The Woodcock-Johnson IV is a comprehensive test evaluating several key areas. These are: general intellectual ability; specific cognitive abilities; scholastic aptitude; oral language; and, academic achievement. This test is designed for ages 2 to 90. There are several advantages of this test. First, it is not timed, so there is less pressure to work quickly. The test is primarily verbal and visual so that reading disabilities do not impact the score. The test can be taken in several sessions so that difficulties with sustained concentration do not affect the score. This test can help pinpoint a student's areas of strength. It also identifies preferred learning style; aptitude in different academic areas; and, the presence of visual perceptual difficulties, if any.
Wechsler Individual Achievement Test (WIAT)
The Wechsler Individual Achievement Test is an academic achievement test designed by the same authors who developed the Wechsler IQ tests. Testers can easily make comparisons between the WIAT and Wechsler IQ scales. This comparison helps to identify discrepancies between achievement and IQ. The pattern of these discrepancies can signal any number of possible diagnoses (e.g., learning disabilities). WIAT test scores can be used to compare a child's current achievement level with that of his or her peers. All tests, except for the written expression subtest, are administered without required time limits. This allows students to demonstrate their actual knowledge and skill, rather than simply their speed.
Wide Range Achievement Test (WRAT)
The WRAT is designed to measure reading recognition, spelling, and math computation. There are two versions of the instrument: one for ages 5 to 11; and the other for ages 12 and over. This test may not be the best choice for children from minority groups, because it was not developed to correct for cultural differences. Despite its limitations, the test can be used to determine learning abilities and disabilities, and to assess error patterns that could be helpful in planning specific instructional programs.