The environment in which most organizations function today is constantly changing. Therefore organizations need to appropriately change to cope with the external change. Secondly, organizations and systems may need to change because they function in a static environment or an oppressive environment. In this case both the organization and environment would need to change.

A third situation when change may be required is when the systems, structures, processes and technology (SSPT) prevalent in an organization are inappropriate to the goals (G) of the organization. Sometimes goals may need to be changed to match the SSPT.

Most organization development effort necessitates some change at one or more of the following levels.

• Within the individual (intra-personal)
• Between individuals (Inter-personal)
• Between groups (inter-group)
• Between organization and environment
• Various groups/systems in environment and the organization.

The basic assumption of OD theory and practice is that change can be planned for and managed by an insightful diagnosis of the prevalent situation in the organization and by suitable followup action.

Traditionally, OD has placed a great deal of emphasis on the ‘laboratory approach’ to learning. This approach has increasingly focussed on ‘here and now’ processes, with simultaneous emphasis on feelings and emotions, as well as tasks, ideas and concepts. It also gives a very important place to the individual’s ability to give and accepts feedback about reality. The group is present to put together individual perceptions so as to form a workable plan of action for change. The group also is expected to provide emotional support and meaning to the individual especially in relation to work.

It is because of these and other historical reasons there has been in OD quite frequent use of behavioural science insights and tools.