There are three basic concepts of human behavior that form the foundation of the generalist human service workers' responsibilities. These are:

1. Intervention
2. Professionalism
3. Education
Intervention involves the period in which a client exhibits a need for services, and calls upon the human service worker for help. Professionalism is using the skills acquired through formal education and obtaining the award or degree for this education. Formal education is the actual classroom academic training and research in addition to hands-on training through field internships.
The Start of Human Services
Social reforms and legislation actually began in England. The Elizabethan Poor Laws initiated the idea of compulsory taxation to raise funds for helping the needy. These laws also started establishing eligibility requirements for recipients. The early developments in English social reform and legislation are the bridges to contemporary human services in the United States today.
There are three primary models in the helping profession. They are:
1. Medical model
2. Public Health (social welfare) model
3. Human Service model
The human service worker trained as a generalist is unique in its view of people, services, and the social environment as integrated entities. The other models have individual ideas as what is the cause of people's problems and concentrate on those specific areas. For example, the medical model concentrates on the individual and sees clients as needing help because they are sick physically. The human service model expects disease and social problems to always affect people. Their focus is upon providing services to help individuals deal with problems stemming from disease and social problems. For example, a particular disease might cause disability, loss of jobs, loss of housing. The human service worker works toward finding resources to help the individual stay independent or become independent once again.
The absolute main function of human service workers is "crisis intervention." Crisis intervention is required when a client experiences sudden disruption such as a sudden death of a spouse or parent, a catastrophic event such as a hurricane that destroys all the client's belongings and leaves them suddenly homeless. Crisis intervention is the consequence of a sudden disruption in a client's life. The human service worker is called upon to help the client deal with the crisis and work toward the client's independence.
Every client lives in a micro and macro social system. The human service worker is enmeshed in the two systems.
The micro system includes:
1. individuals
2. small groups
3. families
4. couples
The macro social system includes:
1. large groups
2. organizations
3. communities
4. neighborhoods
5. bureaucracies
The generalist human service worker's treatment plan includes all the remedial efforts directed at the resolution of a client's problems within the context of the social environment. Ideally, the client and human service worker move through the micro and macro systems in a dynamic process and are each bound by their social roles.
Source: Human Services, Contemporary Issues and Trends (3rd ed.) David C. Maloney, Franklyn M. Rother