OBE is a belief that students need to master each concept before they go on to the next concept. Students may take post-tests over and over until the students finally show mastery. Mastery is usually set at 80. OBE teachers keep elaborate computerized records on the mastery level of each student so that the correct retest can be administered.
Students progress at their own speed as they master each unit.
All students are basically working on individualized plans. Many educators bought into the idea in the early 1990's led by such states as Pennsylvania, Oregon, Kentucky, and Colorado. The problem is that students are natural procrastinators when allowed to be. If students know they can always take a retest, they simply do not study the first time. The teacher and students all start out on the same page the first day of school.