Credit rating agencies (CRA) are qualified as “auxiliaries of the financial information” by all the investors. Ratings are the results of a methodology used by CRA. Within the framework of a demystification of the method of work of agencies, the objective of this paper is to identify the importance of the accounting and financial information adjustments in the decisions of rating agencies. This allows estimating the explanation proportion of this type of information that contributes in the development of the assigned rating. We suggest a statistical and econometrical study that aims at determining the ratings from the accounting and financial variables adjusted by the credit rating agencies to better understand the relation between the adjustments of the ratings and the level of the ascribed score.