This chapter discloses the general sample and the general methodology to be used throughout the book, to assess ratings accuracy and methodological particularities will be discussed at the level of each test. In order to do so we present the sample; examine the test of the fit to the data of agencies model, using constant analysis, residual analysis and gap analysis; discuss the test of subjectivity in the sovereign ratings; discuss the test of the overall accuracy and transparency of agencies model; and conclude the chapter.