aimswebPlus® is an assessment, data management, and reporting system that provides national and local performance and growth norms for the screening and progress monitoring of math and reading skills for all students in kindergarten through 8th grade. aimswebPlus uses two types of measures: (1) "curriculum-based measures" (CBMs)--brief, timed measures of fluency on essential basic skills; and (2) "standards-based assessments" (SBAs)--comprehensive measures aligned to current learning standards. By combining these two types of measures, aimswebPlus provides the data that schools need for program planning and evaluation and for tiered assessment (multi-tiered system of supports [MTSS], also known as response to intervention [RTI]). Furthermore, aimswebPlus data provides teachers with the information needed to differentiate instruction and determine who will benefit from intensive intervention. The three assessment quality criteria discussed in this report are the extent to which the assessments allow educators to make sound interpretations of student skills (validity), the consistency and accuracy of scores (reliability) and the fairness of the assessments (AERA, APA, & NCME, 2014). aimswebPlus assessments consist of brief, standardized measures of skills in early literacy, reading, early numeracy, and mathematics that are extensively supported by both published research and Pearson-conducted studies. This report summarizes this research by content area (Early Numeracy, Math, Early Literacy, and Reading).