SC105. TESTA Presents: CER--Baby Steps for Teachers and Students Tired of reading student reports and essays lacking focus and scientific backing? Don't have time to collaborate with other teachers on how to improve student writing? CER has the answers. CER (Claim, Evidence, Reasoning) is a format for writing about science. It allows students to think about data in an organized, thorough manner. According to the CER model, an explanation consists of a claim that answers the question, evidence from students' data, and reasoning that involves a "rule" or scientific principle that describes why the evidence supports the claim. Teachers will gain an understanding of CER, how to introduce it to their students, and how to assess student ability to write well-thought-out explanations. They will experience card sorts, interactive notebooking, whole- and small-group activities, and higher order questioning strategies.