Answer:
1. A subjective social or religious issue that uniquely affects education
Issues like gun control, gender ed, prayer, creation v. evolution, and spanking in schools are, for the most part, matters of personal opinion. Implementation of rules regarding such issues may be based on legal precedent or pressure from political, administrative, or parental authority, but when opposing perspectives among interested parties converge, controversy is inevitable.
2. A deviation from traditional methods
Educational practices, teaching methods, and curriculum vary from school to school; nevertheless, in most public schools in the U.S., there exists a basic concept of education. Children are required by law to attend an educational institution whose responsibility is to impart knowledge and understanding of the traditional subjects: mathematics, English, social studies, and sciences. A certain level of non-traditional teaching style and the subject emphasis is generally tolerated or desired, of course, but when non-standard educational movements become broad, such as flipped schools, MOOCs, or homeschooling, or threaten to affect traditional schools, like same-gender schools or integration of students with special needs, controversy ensues.
3. A potential “corruption” or harming of students
Education is intended to provide knowledge, skills, and discipline; educated students are prepared for careers, personal fulfillment, inter-personal relations, and general life navigation. Sometimes, however, a school or instructor distorts those objectives, intentionally or not, and physically or ethically obstructs the goals of education. The controversy lies in the perspective: to some, educational research that depends upon real classroom conduct is progressive or necessary, while to others, emotionally or intellectually manipulating students or grades amounts to exploitative human experimentation.
4. Shown to be historically, scientifically, or socially incorrect
From a more historical standpoint, some of the controversial practices included in this list are no longer legal or fashionable but are nevertheless prime examples of contentious topics in education. It is precisely because of the controversy that practices like racial segregation have been challenged, disproven, and abolished, but in some cases, despite evidence to the contrary, questionable educational practices persist.
