The National Recovery and Resilience Plan (NRRP) included measures to reform the public administration and develop administrative capacity at central and local level, both in terms of human capital (selection, skills, careers) and simplification of administrative procedures. With regard to the main axes of the reform (access, good governance and human capital) and the analysis of the structural evolution of the PA in terms of employment, the need for an up-to-date and reliable framework of indicators to monitor the actions implemented and, if necessary, to take corrective measures was immediately apparent. In particular, in the context of the “Access to PA” reforms, while the development, implementation and integration of the main platforms used make it possible to monitor the evolution of selection and recruitment procedures in PA, there is a lack of up-to-date information on flows of actual entries and exits. For this reason, it was decided to make use of the wealth of information offered by the system of compulsory communications, that is an administrative source on employment flows, which provides timely, granular data with a high degree of coverage in terms of employers and workers. The purpose of this document is to describe the structure of the data of the Statistical Information System of Compulsory Communications (SISCO) to be used for the production of statistical information on quarterly flows of activations of employment relationships by public administrations. The ultimate objective is to compile the number of actual activations of employment relationships in a given quarter.