In this technical report, we document the development and piloting of easyCBM reading measures aligned to the Common Core State Standards, designed for use in screening students at risk for reading difficulty and monitoring their progress as they develop reading skills. The measures, which assess students' ability to respond to multiple-choice reading comprehension questions, were designed with the specific needs of students classified as "persistently low-performing". Sub-tests include "Read to Perform a Task, Informational Text," and "Short Literary Text," organized together into a comprehensive Common Core Reading Assessment. We begin this report by introducing the student population for which these measures were originally developed. Then, we describe the two main approaches used in the development of the measures, with a focus first on content validity and then on the psychometric properties underlying the creation of comparable alternate forms. We include the results of our Item Response Theory (IRT) modelling used during test development. For ease of reference, we present the results for each grade level's analyses in its own technical report yet repeat the introductory sections across all technical reports in this series, as the development process and the research base on which these assessments were developed does not vary by grade.