Research and the practice of social work focuses on areas such as: addictions and mental health, assessment and diagnosis, human development, psycho-social and socio-legal issues related to child and family welfare, community and social development, counselling, diversity, marginalization and oppression, policy analysis and development, psychotherapy, public administration, social planning, social policy and social program evaluation. Social workers are organized into local, national, continental and international professional bodies. It is an interdisciplinary field that incorporates theoretical bases from anthropology, ecology, economics, education, law, medicine, philosophy, politics, psychology, sociology and science.