The ASA system is a performance objective educational system. This means that any qualified individual can be certified to his/her level of competency. If a sailor does not feel the need to take a given course to become certified, he or she my "challenge the Standard". The ashore and afloat requirements for each given standard do not change. Neither does the accumulative requirement of passing each certification level step by step. Typically the challenge would consist of a sailing checkout and completion of the appropriate written examination.