Groups may be classified into different types. The basis of differentiation may be purpose, extent of structuring, process of formation, and size of the group membership.
1) Primary and secondary groups: primary groups are those characterized by intimate, dace-to-face association and co-operation. For example, family , and peer group.
Secondary groups are characterized by large size and individual's identification with values and belief prevailing in them rather than actual interaction. For example, occupational association and ethnic groups
2) Membership groups and reference groups: membership groups are once to which the individual actually belongs. For example- clubs, co-operative societies, workers union, etc.
Reference groups are the once with which an individual identifies or to which he would like to belong.
3) In-groups and out-groups: in-groups represents a clustering of individuals holding prevailing values in a society or at least having a dominant place in social functioning. For example: members of a team, family members, etc.
Out-groups are the messes or conglomerate viewed as subordinate or marginal in the culture. For example: street performers for an office worker, a hawker for a surgeon.
4) Interest v. friendship groups: interest group involves people who may come together to accomplish a particular goal with which they are concerned.
Friendship groups are formed by people who have one or more common features. People coming from a particular region or holding a particular viewpoint or speaking a particular language tend to form friendship groups.
5) Formal and informal groups: formal groups are established by the organization to accomplish specific tasks. It is a designated work-group defined by the organizational structure. It includes.
a) Command groups: command groups are composed of the suordinates who report directly to a common superior. For example: a college principal and teachers, a production manager and his subordinates in his department and so on.
b) Committees and taskforces/groups: committees and taskforces are created to carry out specific organizational assignment or activities.
Informal groups are those groups, which appears in response to the need for social contact. These groups are formed within the structure of the organization but by the members themselves. They are formed to satisfy the social needs on the job.
6) Temporary and permanent groups: groups are formed for achieving certain objectives. They have a very short life. After attaining the objectives, they are dissolved. Solving problems and discussing ideas are the main functions of temporary groups. Meetings, committees, and small groups are examples of temporary groups.
There are certain natural and permanent groups. They have group activities, group performances, job assignments and so on. A team is a permanent group. Trade union and business associations are examples of permanent groups.
7) Nominal and non-performing groups: nominal groups are presented with problems to be solved. Members of the groups share their ideas in a structured format. Their alternative suggestions are discussed for arriving at more effective suggestions. This is a nominal group because the employees are members of the group for name sake only.
Non-performing groups are only on paper. They are formed and developed without any performances. They have certain goals but there is no attempt to achieve those goals.