The Next Generation Science Standards (NGSS) define science literacy as having the knowledge and understanding of scientific concepts and processes and the ability to question natural world phenomena (National Research Council, 2012). When students work with texts that deal with real world issues, they can look for claims supported by evidence (Berland, et al., 2017; Levin et al., 2021) and work with reasoning of other students through interactive conversations about the data and sharing of ideas (Michales & O’Connor, 2017). Therefore, integrating scientific arguments into the classroom is an important step in developing scientific literacy (Cavagnetto, 2010) as it helps students engage in authentic learning through a variety of practices and methods to construct and evaluate claims (Ford, 2012). In our teaching and professional learning programs, we address the question of how to meaningfully assess students' science literacy and ability to engage in science argumentation through a CER framework that incorporates the Next Generation Science Standards (NGSS, 2013). The answer to our inquiry was the development of Scenario-based Assessments (SBA). This article explains the elements of an SBA and presents the findings of using SBAs in middle and high school STEM classrooms.