Student centered assessment

In my classroom, student-centered assessment happens on 2 levels. The first is informally finding out what the student learned, what he thinks he learned and what he still isn't sure about. This is accomplished through whole class or small group discussions. Once our class discussion is finished, students are sent back to their seats to either complete a writing/drawing graphic organizer or to make an entry in their writing journals. By having something in writing, I am able to check individual progress of each student, including ones who may not have chosen to participate in the class discussion.