Schools are required to take such measures as are reasonable to prevent physical injury to a pupil. The duty of care owed by a school to a student goes beyond the duty of parents to their children. This duty exists at all times when the child is under the control of the school and even beyond the school grounds in some cases. A school's responsibility is sometimes very great, such as during school excursions. In each case, the likelihood of risk to the students should be assessed and adequate precautions taken. Generally a school would not be liable for an injury to a student as long as there was adequate supervision, the dangers were understood and anticipated and reasonable precautions were taken.

To have a case against a school, an injured student must be able to prove:

Supervision must be adequate at all times when a child is under the control of the school, not only during classroom activities but at other times such as before and after school, during breaks, and school excursions.

Schools are not required to have a teacher observe and supervise every incident in the school yard, or even in the classroom. A court would look at the number of students in the area; the foreseeable risk to students; the number of teachers assigned to oversee the activities of those students and their diligence in supervising the area.