In this technical report, we describe the results of a study of mathematics items written to align with the Common Core State Standards (CCSS) in grades 6-8. In each grade, CCSS items were organized into forms, and the reliability of these forms was evaluated along with an experimental form including items aligned with the National Council of Teachers of Mathematics (NCTM) Focal Point Standards. The purpose of the experimental measure was to evaluate how previously existing math items functioned empirically relative to the CCSS items. All included NCTM items were previously rated as linked with the CCSS. Analyses included Rasch modeling to explore the difficulty and functioning of both sets of items, classical reliability statistics (Cronbach's alpha, testretest, and alternate form reliability) and two sets of Generalizability Theory analyses. Overall, results suggest the CCSS items are more difficult than the NCTM items, and test forms made up exclusively of CCSS items operate at less than ideal reliability levels. The ways in which the results of this study have informed revisions to the easyCBM CCSS Math test forms to enhance the reliability while increasing accessibility are discussed. The following are appended: (1) Teacher Instructions; and (2) Complete Generalizability and Decision Study Results.