(14)In relation to experience test requirements, while assessing whether the rating systems used by the institution prior to the application to use the IRB Approach were ‘broadly in line’ with the IRB requirements, competent authorities should verify in particular that during at least three years before the use of the IRB Approach, the rating system has been used in the internal risk measurement and management processes of the institution and that it has been subject to monitoring, internal validation and internal audit. Such specification of the assessment methodology is necessary to ensure a minimum level of harmonisation. Competent authorities should verify that rating systems have been implemented in at least the most basic areas of use to ensure that the rating systems have been effectively used by the institution and that both the personnel and the management are accustomed to those parameters and understand well their meaning and weaknesses. Finally, monitoring, validation and internal audit during the experience period should show that the rating systems were compliant with the basic requirements of the IRB Approach and that they were gradually improved during that time.