Being a member of a group, such as a class or cohort, influences and shapes the behaviour of its members. Each group has its own unique sub-culture of values and expectations of its members. The formation of social rules within the group is complex and involves a multitude of external influences such as the school culture, local community and wider societal values. Equally, the group's sub-culture reflects the personalities and behaviours of its members and in particular the more dominant 'role-models'.
In terms of classroom management these differences between classes, forms and cohorts can be significant. Many experienced teachers report classes that are more challenging or wearing than others. Sometimes this is because of high numbers of students with additional needs and sometimes it is due to a lack of social cohesion or maturity. Assessing the needs of the class or form as a single entity can be as important as the assessment of the individual needs of its members. Identifying areas of common need provides the opportunity to address them more efficiently.