The evaluation of non-cognitive variables, such as personality factors, is key in personnel selection processes in public administration, although its application presents certain challenges. This article addresses the need to ensure the validity of these processes by integrating the principles of transparency and publicity with best practices in the use of tests. Based on the report from the Test Commission of the General Council of the Spanish Psychological Association on the use of psychometric tests in selection processes in public administration, 16 recommendations are provided, organized into seven areas: objectives, test application, scoring, selection criteria, reports, functional diversity, and qualifications. It is of vital importance to document and justify each stage to guarantee fair and wellfounded decisions. These guidelines solve some issues that arise in the application of non-cognitive tests, and ensure alignment with the principles of publicity, transparency, and fairness in public sector selection.