To ensure that student academic growth in a subject area is accurately captured, it is imperative that the underlying scale remains stable over time. As item parameter stability constitutes one of the factors that affects scale stability, NWEA® periodically conducts studies to check for the stability of the item parameter estimates for MAP®…

Assessing students' emerging literacy skills is crucial for identifying areas where a child may be falling behind and can lead directly to an increased chance of reading success. The Waterford Assessment of Core Skills (WACS), a computerized adaptive test of early literacy for students in prekindergarten through 2nd grade, addresses this need.…

Development of adaptive tests used in K-12 settings requires the creation of stable measurement scales to measure the growth of individual students from one grade to the next, and to measure change in groups from one year to the next. Accountability systems like No Child Left Behind require stable measurement scales so that accountability has…