This article analyzes the quality dimension of methodological clarity of the National Registry of Health Establishments (CNES), considering the approach to forms of contracting in the system. This is a documentary research with a qualitative approach, which analyzed the CNES and its documents. Documents that included the following were selected: table of professional relationships and/or forms of hiring. Based on the concept adopted for the dimension of methodological clarity quality, the categories accessibility, content, variables, language, and usability were outlined. In the period from 2005 to 2020, 17 documents were published. Of those, three documents stood out: The version’s Readme, the Domain Table, and the CNES Filling Manual. The CNES website underwent restructuring and not all features were completed. The current website has a more modern and easy-to-understand interface. The change from the administrative sphere variable to the legal nature, in 2015, may make historical series analysis difficult. It is evident that the CNES pays more attention to methodological clarity, considering the approach to the ways of hiring health professionals, included in the system.