An Evaluation of Healthcare Policy in Immunisation Coverage in Uganda Agnes Semwanga Rwashana and Ddembe Wileese Williams Information Systems Dept, Faculty of Computing and Information Technology Makerere University P.O. Box 7062, Kampala, Uganda, East Africa Tel: +256-41-540628 / Fax : +256-41-540620 asemwanga@cit.mak.ac.ug / d.williams@cit.mak.ac.ug Abstract. This paper presents initial results from fieldwork on immunization coverage as part of improving health care policy implementation in Uganda. System Dynamics modeling and case study research methods are used to capture the complex and dynamic nature of the immunization process, to enhance the understanding of the immunization health care problems and to generate insights that may increase the immunization coverage effectiveness. Field studies have been conducted to establish the operational immunization policy issues of concern to health care management, which included capturing reference modes for the key variables and developing causal loop diagrams to illustrate the dynamics among key variables. The paper suggests an initial model that could be used for theory building in immunization policy evaluation. Keywords: System Dynamics, Modelling, Feedbacks, Delays Immunization Coverage, Health care policy ______________________________________________________________________ Introduction Understanding immunization health care policies is arguably one of the most important processes in evaluating health care strategies to eradicate childhood diseases. Increasing immunization coverage to prevent childhood diseases has become an important developmental issue (DISH 2002; WHO 2002; WHO 1999) and an area of critical research (Dexter et al. 1999; Edmunds, Hethcote 1997; Stafford and Aggarwal 1979; Subramanyan and Sekhar 1987). While global coverage for DPT3 (three doses of the combined Diphtheria/ Pertussis/Tetanus vaccine) remains between 70-76 per cent since 1990, significant variations exist between and within regions and countries. Coverage for South Asia and Latin America remain stagnant at 71 per cent and 89 per cent respectively. The Central Eastern Europe and the Commonwealth of Independent States (CEE CIS) region are experiencing a decline to 88 per cent. Sub-Saharan Africa, for example, lags behind, but continues to make steady progress with coverage at 60 per cent estimated in 2003 (UNICEF 2004). Immunization coverage is lowest in poor countries and among poor populations (Gwatkin 2001). Although an effective measles vaccine was licensed in 1963, almost 30 1