As explained elsewhere on the Poorvu Center website, Turnitin alone cannot prove that a student has plagiarized. But if you suspect plagiarism—whether before or after reviewing a Turnitin similarity report—your school probably has specific procedures in place for addressing these concerns. Yale College offers both formal definitions of academic integrity [1] and a specific set of processes for reporting suspected violations [2]. For courses outside of Yale College, please contact the respective Dean’s office [3].