AIDSQuest: The HIV/AIDS Survey Library
Behavioral and Social Theories Commonly Used
in HIV Research

C. Ecological Systems Theory

There are a number of different versions of ecological models, but in general they recognize that successful activities to promote health, including HIV risk reduction, involve not only changing individual behaviors, but also advocacy, organizational change, policy development, economic supports, environmental change, and multi-method programs. According to this model, behavior is determined by the following:

1. Intrapersonal factors—characteristics of the individual such as knowledge, attitudes, behavior, self-concept, skills.

2. Interpersonal processes—formal and informal social network and social support systems, including the family, work group, and friendships.

3. Institutional factors—social institutions with organizational characteristics and formal and informal rules and regulations for operation.

4. Community factors—relationships among organizations, institutions, and informal networks within defined boundaries.

5. Public policy—local, state, and national laws and policies.

Interventions are more successful if they intervene within  most, if not all, levels of influence. For example, distributing condoms can reduce barriers such as price and convenience, as well as change the social acceptability of carrying condoms.

Bronfenbrenner, U. 1979. The Ecology of Human Development. Cambridge, MA: Harvard University Press.

U.S. Department of Health and Human Services. "National Institutes of Health: Theory at a Glance: A guide for health promotion practice," http://oc.nci.nih.gov/services/theory_at_a_glance. Accessed 22 May 2002.