Though argumentative writing is a vital skill across diverse content areas and domains, most U.S. students perform below grade level in writing, and teachers are often unprepared to address this shortfall because their training approaches writing as a subspecialty of reading rather than its own unique discipline. Writing instruction and assessment need more approaches and broader perspectives to foster students' motivation and engagement. To that end, the research team developed an innovative formative writing assessment exercise and scoring rubric focusing on analytic skills and the personal meaning-making process of argument writing rather than the technical skills of grammar, punctuation, and spelling. Integrating a visual literacy and arts component into the writing protocol as an alternative to a text-based prompt to enhance students' engagement in writing. The scoring rubric design aimed to be generally applicable to a variety of different kind of prompts, providing anchors alongside detailed criteria for each aspect of argumentative writing included. The team also surveyed students' perceptions of different factors including self-efficacy for argumentation, self-efficacy for close observation, critical thinking, intrinsic enjoyment to write, openness to different perspectives, and sense of belonging in the class. The results emphasized the importance of students' self-efficacy in argumentative writing and provide initial evidence that the proposed approach has promise.