The document discusses the roles and types of assessment used in classroom instruction. There are four main roles: placement assessment at the beginning to determine student knowledge and skills; formative assessment during instruction to monitor progress; diagnostic assessment to identify weaknesses; and summative assessment at the end to evaluate learning and teaching effectiveness. There are also different types of assessments discussed like traditional, alternative, performance-based and portfolio assessments. Effective assessment requires clear learning objectives, a variety of procedures, relevance to instruction, adequate samples of student work, fairness, specified evaluation criteria and feedback to students.