These are two systems for sorting children into different teaching groups by academic ability. Streaming involves assigning children to a class for all subjects, on the basis of general ability. Setting is used for particular subjects (most often maths and languages) − so a pupil can be in a high set for maths but a lower one for French – or vice versa. Children are assigned to particular sets or streams on the basis of performance in exams and in class.

The advantage of setting is that groups of similar ability in a subject are easier to teach, thus preventing quick learners from being held back and allowing slower ones to move at a less pressured pace. The disadvantage is that children can be held back by being wrongly setted, particularly if movement between sets is difficult.

Streaming is most often used where the school takes a broad ability range and allows it to teach generally bright pupils separately from those that need to go at a slower pace. The disadvantages are that it is more difficult to move up a stream than it is to move down; that strengths and weaknesses may vary from subject to subject; and that the group dynamics of lower streams can prevent pupils with marked strengths and weaknesses from fulfilling their potential.