This paper try to assess role of credibility in the implementation of inflation targeting framework in Indonesia. It illustrates how credibility may play an important role in the evolution of the Indonesian monetary policy. Knowing the degree of credibility would beneficial for Bank Indonesia (BI) to understand how to adjust policy instrument to achieve a long-term inflation target. Scaled from zero (purely not credible) to one (perfect credibility), our quantitative measurements found that credibility index for Indonesian monetary policy converge to around 0.5. Refer to projection and simulation results in this paper, the study shows expectation inflation of economic agents is strongly influenced by monetary policy credibility. The more cr...