Literature dealing with the third sector generally distinguishes between two basic types of NGOs: service and advocacy. The first type focuses its attention primarily on providing services of various kinds; they cooperate or compete with commercial or state organizations providing similar services and try to hold their own by means of the efficiency and quality of the services offered. The second type concentrates chiefly on defending the rights and interests of various
groups of people (or public interests); it seeks to influence the decisions of public administration and it mobilizes the general public in support of its demands. In these activities they interact both with representatives of the public administration and with political parties and various interest groups.