The Moderating Influence of Student Characteristics on the Stability of Reading and Mathematics Assessment over a Five-Year Period.

Stability of measurement of basic achievement skills in reading and mathematics was evaluated for a large special education population. Test-retest coefficients computed over a five-year interval for the hearingimpaired modification of the Stanford Achievement Test generally reflected adequate stability for a national sample of special education students in the primary to secondary age range. Additionally, a significant moderating influence of ethnic background on stability was found; lowest stability of measurement estimates were derived for black hearing-impaired students. However, the major handicapping condition of the population, degree of hearing loss, did not differentially affect measurement stability.