During the past 2 decades, significant changes in mathematics curriculum standards and policies have brought greater attention to assessment instruments, practices, purposes, and results. In moving toward stronger accountability, the No Child Left Behind Act (NCLB) of 2001 (NCLB, 2002) mandates that school districts receiving funding under NCLB formulate and disseminate annual local report cards that include information on how students and each school in the district performed on state assessments. This mandate has not only facilitated a growth in state testing (Wilson, 2007) but also influenced the teaching of mathematics (Seeley, 2006). More recently, the National Governors Association Center for Best Practices (NGA Center) and the Council of Chief State School Officers (CCSSO) crafted and launched the Common Core State Standards for Mathematics (NGA Center & CCSSO, 2010), which have been formally adopted by the vast majority of U.S. states and territories. The Common Core State Standards for Mathematics (CCSSM) specifies standards for mathematical content by grade in K–8 and by conceptual categories at the secondary level and identifies key Standards for Mathematical Practice that should be present in K–12 instruction. The CCSSM represents an unprecedented initiative to raise academic standards in school mathematics that will inevitably influence the development of curriculum materials, teaching, and assessment practices.