Community can be defined from four perspectives: social science, institutional, civil society, and local/grassroots. The social science perspective defines community as a group interacting in an area, while the institutional perspective sees communities as organized groups. Civil society links people through common interests and collective action. The local perspective emphasizes self-organization and volunteerism at a community level. An effective community has aspects related to demographics, geography, beliefs, politics, economy, education, health, and sources of information. Dynamics like community power, leadership, relationships, and social change are also important.