Mario Claasen holds a Bachelor of Social Science (Honours) in Public Policy from the University of Cape Town and is currently completing his Masters thesis in the same field. He was a founder member of the Treatment Action Campaign (TAC) in 1998 and has been an active volunteer since the TAC’s inception. He completed an internship with Health Systems Trust in 2002, working on the Local Government and Health Project. In 2003, he joined the TAC as a staff member as the Clinics Co-ordinator. In this capacity, he was responsible for implementing a clinic assessment study in six provinces, capacity building of TAC members on health systems, local government systems and structures and the participatory development of advocacy strategies at community level. During his time with the TAC and through his studies, he developed a key interest in public budgeting processes and advocacy, with a focus on the health sector.

Mario joined Idasa's Children’s Budget Unit in March 2006. He has been responsible for promoting a child’s rights approach to budgeting through capacity-building with Members of Parliament at national and provincial level; investigating and researching HIV/AIDS programmes targeting children in Health and Social Development Sectors as well as Social Welfare Services programmes at national and provincial level, coordinating the Regional Imali Ye Mwana (Money for Children) Network that is responsible for the promotion and advocacy for children’s socio-economic rights to be advanced through the national budget in the Southern African region. Currently, he is the project manager of the Affiliated Network for Social Accountability (ANSA) in Africa. In 2009, he will be responsible for the overall management and implementation of this project which has been located in Idasa’s Economic Governance Programme.