Teachers have used various methods to cheat on standardized tests, according to the document. These methods include distributing study guides with test questions, signaling answers to students during tests, erasing incorrect answers and writing in correct responses, and using codes or phrases to suggest changing answers without directly giving them away. The cheating has increased as test scores are now being used in teacher evaluations, and many schools and educators have faced investigations and consequences like job losses or charter school closures when cheating is discovered.