The main question of this research is this: what mechanisms drive the increase of the share of health costs in GDP in Germany? Answering this question not only improves our understanding about health systems in general, but also is specifically useful for the health system of Iran, since it is experiencing similar trends as the health system of Germany does. Since these mechanisms are complex and the ability of human brain to process several interacting variables simultaneously is low, we need a strong methodology and a tool to overcome this limitation. System thinking as a methodology and system dynamics as its tool help us do so. Using system dynamics, we will develop a computer model...