Purpose: Much of the recent research on data-driven decision making in US schools has focused on standardized test scores while other forms of data in schools have gone largely unexamined as useful data, such as teacher-assigned grades. Based on the literature, the theory outlined in this paper is that grades, as data historically overlooked in schools, are a useful multidimensional assessment for decision making by educational leaders. This paper aims to address these issues. Design/methodology/approach: Using multidimensional scaling, grades, and standardized test scores are compared for 195 students in grades 9-12 from two US school districts. The relationship between these assessments is visualized between grades in core subjects, such as Mathematics and English, non-core subjects, such as Art and Physical Education, and standardized test scores, such as the ACT. Findings: Two significant dimensions appear to be embedded within grades; assessment of academic knowledge and an assessment of a student's ability to negotiate the social processes of school. These findings indicate that grades should be reconceptualized as informative for data-driven decision making in schools as a potential assessment of both academic knowledge and a student's ability to negotiate the social processes of school. Originality/value: Grades have been overlooked as useful data in the data-driven decision-making literature. This paper provides novel evidence for the usefulness of actual teacher-assigned grades in school and district decision making as well as research and policymaking versus the past use of student self-reported grades or teacher perceptions of grading practices. (Contains 2 figures.)