In 2016, analysts at Marzano Research identified a focused set of content for each K-12 grade level in English language arts (ELA), mathematics, and science called The Critical Concepts (Simms, 2016). Using a set of source standards that included the Common Core State Standards (CCSS; National Governors Association for Best Practices & Council of Chief State School Officers, 2010a, 2010b), the Next Generation Science Standards (NGSS; NGSS Lead States, 2013), and a synthesis of pre-2008 standards from Making Standards Useful in the Classroom (MSU; Marzano & Haystead, 2008), an eight-phase analysis was performed: (1) During phase 1 each standard was separated into component parts; (2) During phases 2 and 3, the component parts were categorized and sub categorized into groups of related content identified as "elements"; (3) During phase 4, covarying elements were grouped into measurement topics; (4) Phase 5 classified each element as (a) content that should be taught, and formally assessed; (b) content that should be re enforced, but not formally assessed, and (c) content that is so general that it is implicit in other elements; Phase 5 also involved reviewing the tentative titles of measurement topics and making revisions for clarity and specificity; (5) Phases 6 and 7 involved articulating learning progressions for the elements in each measurement topic, presented as proficiency scales; and (6) Phase 8 involved three rounds of review and revision, during which proficiency scales were evaluated for adherence to specific criteria (including unidimensionality, covariance, and internal alignment). This report presents a post-hoc alignment between the Critical Concepts measurement topics and the source standards used in the analysis. [Detailed descriptions of each phase can be found in "The Critical Concepts (Final Version: English Language Arts, Mathematics, and Science," (ED574869).]