This Assessment chapter is meant to help teachers identify the components of an argument in students’ work and how to use the rubric to provide feedback and grading. Student samples are provided and identified as high, medium, and low based on quality of the work rather than on grade or age level. These samples were collected from different students, in different classes, at different schools, engaging in the activities at different points within their curriculum. The samples are followed by a scored rubric and descriptions of scoring for each activity. The samples’ scores identify how well and in what ways the student successfully met the criteria for demonstration of content knowledge, of skills in developing a scientific argument, and of written communication skills.