The claim that exercises in US university courses are formally graded to assess student performance is a matter of everyday observation and institutional reality in higher education, requiring no formal citation.
The statement describes a fundamental, universally recognized administrative practice of universities (formal grading of coursework) that is trivially true by definition and institutional observation. Following Step 0, statements that are common knowledge require no citations and are not treated as empirical hypotheses needing literature support. Consequently, the balance verdict is COMMON_KNOWLEDGE with empty index lists.