Examining a Grade-Level Math CBM Designed for Persistently Low-Performing Students

Students with disabilities participate in two major measurement systems. The Individuals with Disabilities Education Act emphasizes working within a Response to Intervention (RTI) framework to identify and monitor the progress of low-performing students. Persistent low-performing students also may be eligible for some form of an alternate assessment for accountability purposes. Working within these two systems, educators need technically sound measures to inform decision making. This study presents scaling results from a Curriculum Based Measurement tool designed within an RTI framework and specifically for persistently low-performing students. We use the phrase "persistently low-performing students" to refer to a specific group of students who have been identified with a nonsevere learning disability and who perform well below grade-level expectations. Key findings indicate that items appear to function well in the lower tail of the distribution of students' estimated ability level. Further, the distribution of items is positively skewed, resulting in many accessible items that are most informative for low-performing students. Results provide initial validity evidence for the measurements as one source of data for progress monitoring within an RTI framework and the identification of persistent low-performing students who may be eligible for a large-scale assessment option other than the general grade-level assessment.