Recent English Language Arts standards emphasize teaching students to use text evidence to support their claims and opinions; yet, students often struggle to do so effectively in their writing. To help students develop this skill, clearer understanding of what effective evidence use entails and targeted feedback to guide students' writing improvement are needed. This article describes four criteria to focus on when helping students use text evidence to support their claims or make a case in their writing. The criteria focus on the extent to which the evidence is complete, accurate, specific, and explained (CASE).