To teach students how to write for the workplace and other professional contexts, technical writing teachers often assign writing tasks that reflect real-life communication contexts, a teaching approach that is grounded in the field's contextualized understanding of genre. This article argues to fully embrace contextualized literacy and better teach workplace writing, technical writing teachers also need to contextualize how they assess student writing. To this end, this article examines some of workplaces' best assessment practices and critically integrates them into an introductory technical writing classroom through a method called student-centered assessment instruments. This method engages students, as workplaces engage employees, in the assessment process to identify local requirements for writing tasks. Aligned with theory and practice, this method is not only an effective classroom assessment method, but becomes an integrated part of students' genre-learning process within and beyond the classroom.