In a social structure roles are more important than role occupants. Role occupants in turn divide themselves into sub-groups. According to Johnson it will be manifestly untrue to say that all the stability, regularity and recurrence that can be observed in social interaction are due to normative patterning, roles and sub-groups of various types are the parts of social structure to the extent that stability, regularity and recurrence in social interaction are due to the social norms that define roles and obligation of sub-groups.
Sub-groups and roles are closely linked with each other because all those who are required to perform certain roles have some duties and obligations towards the group to which they belong. The responsibilities of role occupant are of different types and can be broadly divided into obligatory and permissive. Each social structure has also quasi-structural aspect. In complex society there can be standardised or institutionalized norms. Every rigid social structure is bound to result in social disharmony. In a human society its structure must go on changing.