This document discusses different types and purposes of assessment. It describes traditional, alternative, and authentic assessment. Assessment can be for learning, of learning, or as learning. Assessment for learning includes placement, formative, and diagnostic assessment done before and during instruction to determine student needs and monitor progress. Assessment of learning is summative assessment done after instruction to measure proficiency and inform stakeholders. Assessment as learning involves training teachers to effectively assess student learning. The roles of assessment include using placement tests to determine entry skills, formative assessment to monitor learning, diagnostic assessment to identify difficulties, and summative assessment to measure mastery at the end of a course.