This paper will present results from the administration of the LOCUS assessments to measure students’ statistical understanding in grades 6-8 (ages 10 – 13). The development of these assessments utilized an Evidence Centered Design (ECD) (Mislevy & Riconscente, 2006) approach to establish their content validity. After an iterative development process, these assessments were administered to over 2,000 students in the United States. Student performance in each of the four areas of the statistical problem solving process — formulating questions, collecting data, analyzing data, and interpreting results — will be discussed, and examples of multiple-choice items will be provided.