Educators are professionals. One important attribute of professionals is their constant quest for personal growth. Great music educators are lifelong learners who draw on a variety of sources to improve their expertise and effectiveness. In the first part of this topic, the author listed the primary purposes of student assessment, and focused on its role in improving student learning. In this second part of the two-part series, the author addresses the role of student assessment in improving "instruction". He highlights how measuring student achievement can empower individual teachers to assume responsibility for their own professional growth. He then addresses the policy and practical issues associated with using student achievement data in teacher evaluation, a topic that is currently generating a lot of heat nationwide. (Contains 1 figure and 10 notes.) [For Part 1, see EJ950709.]