However, the knowledge provided by the statistics is inseparable from the respect for confidentiality associated to information collected near respondents, and leads to the inevitable legal appeal of "considerations of proportionality", which means that production of statistics has necessarily to operate the practical concordance and the harmonization between the information that should be of public domain and the one that should be kept under secrecy. Only in this way it can be ensured confidence in the Statistical System.
Thus, the following publications (available only in Portuguese), were prepared:
a) Statistical Confidentiality, which collects and organizes legal and regulatory information concerning Statistical Confidentiality, one of the fundamental principles of the production activity of official statistics. It consists of a consolidated document, and of quick-and-easy consultation, providing the necessary information for a good practical application of the principle of Statistical Confidentiality throughout the production process of official statistics;
b) The Confidentiality Charter , formalizes the public commitment assumed in the protection of confidentiality of individual data collected and used for statistical purposes: I) by Statistics Portugal; II) by the Regional Statistical Services of the Autonomous Regions of the Azores and Madeira, which operate as delegations of Statistics Portugal for production of official statistics of national scope and; III) by entities with delegation powers.