Grades 4 and 8 students had shown slow but steady improvement in scores on the National Assessment of Educational Progress (NAEP) mathematics assessment from 1990 until 2013, but performance since then has been lower despite the introduction of the Common Core State Standards for Mathematics (CCSSM) in the early 2010s. This study examined student performance on released items from the 2017 administration of the grades 4 and 8 NAEP mathematics tests, allowing for analysis of students' mathematical knowledge and insight into students' achievement of the CCSSM. Students generally performed well on items testing basic skills, including some key CCSSM topics, but had limited success applying those skills to items addressing conceptual understanding and problem solving. This study yielded no evidence that student performance has changed--overall or for topics receiving more (or less) emphasis in comparison to prior state standards--since the introduction of the CCSSM. In fact, students performed well on many items assessing content de-emphasized in, or even eliminated from, the CCSSM. Thus, the results of this study suggest that, at least as of 2017, the CCSSM was having little impact on student performance in mathematics. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]