Sources of longitudinal achievement data are increasing thanks partially to the expansion of available interim assessments. These tests are often used to monitor the progress of students, classrooms, and schools within and across school years. Yet, few statistical models equipped to approximate the distinctly seasonal patterns in the data exist,…

In elementary school, many children struggle in learning how to read. Some of these struggling readers will be identified to receive special education services as a student with a reading disability (RD), while other students will not be identified to receive such services but will continue to have low reading achievement (LRA). Limited research,…