We have discussed in Chap. 2 that the sources of heterogeneous effects of monetary policy across regions can be viewed from two different perspectives: different structures and characteristics across regions and different behavior of local banks towards credit allocation. In both perspectives, the magnitude and directions of the heterogeneous effects depend on the period under analysis, and the accuracy of the estimates of the effect crucially depends on the adopted measure (Romer and Romer, Am. Econ. Rev. 94:1055–1084, 2004). In fact, as revealed in the preceding chapter, the responses of the regions to monetary policy, observed through regional credit allocation, are quite different from the average response. The responses in one region are not the same as those in other regions.