Any discussion of the management of organisations must begin with an understanding of the nature of human organisations and why they exist. Like the humans that establish them, each organisation exists for a purpose, a set of goals or objectives that have to be achieved or may only be achieved, if people group together and organise themselves (the word "organisation" comes from the Greek meaning 'tool') (Niemark & Tinker, 1986).
An organisation therefore has many purposes such as to give a decent return on investment as in the case of most private sector organisations by selling a product or service. Public organisations such as the National Health Service exist to deliver a public service or promote a social cause in behalf of the government.
Organisations may be classified according to their purpose, and following this convention, Duncan (1983) distinguished six types: (1) private-sector; (2) public-sector; (3) not-for-profit; (4) institutional; (5) voluntary sector, and (6) mixed organisations. Table 1 gives a summary of each of these organisational types, their specific purposes, and examples of each.
Thus, a voluntary sector organisation according to this definition is a temporary or special purpose group that provides services to its members. However, Drucker (1985, p. 105-106) and Kotler et al. (1987, p. 5) classified under what they termed the Third Sector, Not-for-Profits (NFP), or Non-Governmental (NGO) all those organisations that are neither private-for-profit nor not-for-profit public and that exist to serve a social need.
There has been a growing trend in recent years amongst private for-profit businesses to be more conscious about finding ways to address and provide more lasting solutions to social problems like universal health care, global poverty, disease eradication, and hunger. In fact, former Prime Minister Blair recently commented on the growing value of the 'third sector' and hinted that businesses do not limit themselves as "romantic paeans to charitable activism" by getting more involved in dispensing social justice (Bagehot, 2006).
The last four organisational types based on Duncan's typology - not-for-profit, institutional, voluntary, and mixed - could therefore be included in what could be defined as a voluntary sector