The "Next Generation Science Standards" ("NGSS") push students to have "a deeper understanding of content" (NGSS Lead States 2013, Appendix A, p. 4). However, with the reality of high-stakes assessments that rely primarily on multiple-choice questions, how can a science teacher analyze students' written responses beyond "right" or "wrong" given instructional time constraints? To address this issue, the authors of this article set out to design a useful and realistic assessment guide to analyze students' written responses in science. Their assessment guide would be appropriate for intermediate grade levels, grades 3-5, up to middle school, grades 6-8. As they designed their assessment guide, they incorporated the four following factors: (1) simplicity; (2) time; (3) science vs. language arts perspective in relation to students with limited literacy; and (4) meaningful feedback to inform instruction and identified three areas in which to assess students' science writing: science content, science inquiry, and science vocabulary. This article describes how the authors used their assessment guide to analyze written responses from over 350 students (two students from each of approximately 175 classes) participating in their research.