Grading is one of teachers' greatest challenges and most important professional responsibilities. For more than a century, grades remained the primary indicator of how well students performed in school and stayed the basis for making important decisions about students (Guskey, 2015). Traditional grading practices are subjective at best and do not give an accurate description of what students know and understand. Standards-based approaches to grading and reporting require teachers to base grades on specific criteria from standards. Behavior and effort are reported separately. The purpose of this study was to compare the relationship that exists between a traditional or standards-based grading system and achievement on the Scholastic Math Inventory (SMI) assessment. In addition, this study sought to analyze perceptions of teachers who have implemented standards-based grading and to determine these teachers' understanding of how grading has changed their reporting of student learning. This study utilized a non-experimental, causal comparative, ex post facto research design. This study correlated end-of-course math grades with Scholastic Math Inventory scores in a traditional and standards-based grading setting from sixth-, seventh-, and eighth-grade students. A significant, moderate relationship was produced under both grading systems, but slightly higher, more statistically significant results were found under the standards-based grading system in grades 6 and 8. Themes emerged from the interview of the six math teachers during the teacher participant interview. The findings or themes of this study uncovered: the purpose of grading and reporting is to communicate efficiently and effectively to all stakeholders involved in a child's education; grading of content knowledge should be based on specific proficiency levels and not effort or behavior; and teachers use that information from a standards-based approach to differentiate, plan for instruction, and provide specific feedback for student learning. Marzano (2000) believed the most important purpose of grades is frequent, detailed feedback and, therefore, the best reference point must be specific objectives, standards, or other learning goals in which a standards-based system serves this purpose. [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.]