Certification or qualification, is a designation earned by a person to assure qualification to perform a job or task.  One of the most common types of certification in modern society is professional certification, where a person is certified as being able to competently complete a job or task, usually by the passing of an examination and/or the completion of a program of study.  Some professional certifications also require that one obtain work experience in a related field before the certification can be awarded.  Some professional certifications are valid for a lifetime upon completing all certification requirements.  Others expire after a certain period of time and have to be maintained with further education and / or testing.  –¢–