Psychometric stability of nationally normed and experimental decoding and related measures in children with reading disability.

Achievement and cognitive tests are used extensively in the diagnosis and educational placement of children with reading disabilities (RD). Moreover, research on scholastic interventions often requires repeat testing and information on practice effects. Little is known, however, about the test-retest and other psychometric properties of many commonly used measures within the beginning reader population, nor are these nationally normed or experimental measures comparatively evaluated. This study examined the test-retest reliability, practice effects, and relations among a number of nationally normed measures of word identification and spelling and experimental measures of achievement and reading-related cognitive processing tests in young children with significant RD. Reliability was adequate for most tests, although lower than might be ideal on a few measures when there was a lengthy test-retest interval or with the reduced behavioral variability that can be seen in groups of beginning readers. Practice effects were minimal. There were strong relations between nationally normed measures of decoding and spelling and their experimental counterparts and with most measures of reading-related cognitive processes. The implications for the use of such tests in treatment studies that focus on beginning readers are discussed.