In the following technical report, we describe the development and scaling of the easyCBM CCSS middle school mathematics measures, designed for use within a response to intervention framework. All items were developed in collaboration with experienced middle school mathematics teachers and were written to align with the Common Core State Standards. Items were calibrated to a common, vertical scale spanning grades 6-8. The results of the scaling analysis were then used to assemble items into 13 comparable alternate test forms in each grade, with 10 designated for progress monitoring and 3 designated for seasonal benchmarking. Evidence of alternate form equivalence is provided through both test characteristic curves (TCCs) and test information functions (TIFs). Individual item functioning is reported in appendices by both the total pool of items piloted and by test form. The following are appended: (1) Training Materials; (2) Item Statistics; (3) Item Statistics by Test Form; (4) Distractor Statistics; and (5) Distractor Statistics by Form.