In this dissertation, we analyze the Brazilian monetary policy and a group of countries under inflation targeting. Our results indicate that many countries had changes in monetary policy, detected through a break in the central bank reaction function between 2007 and 2009, possibly related to the global financial crisis. We find evidence that the Brazilian central bank lowered its response to inflation deviations from the target and also that inflation expectations became unanchored, suggesting an inconsistency with the inflation targeting regime. Although we detected breaks in almost every country, the two above changes did not occur in most of the countries. Thus, we used these countries to apply the synthetic control method and estimate the trajectory of inflation and GDP growth if the Brazilian central bank had not changed its monetary policy. The results of the synthetic control method suggest that the change in the Brazilian monetary policy resulted in higher inflation and a more volatile GDP dynamic, with limited gains in the period after the change and lower growth in the following years, compared to the synthetic trajectory.