Some perspectives on status emphasize its relatively fixed and fluid aspects. Ascribed statuses are fixed for an individual at birth, while achieved status is determined by social rewards an individual acquires during his or her lifetime as a result of the exercise of ability and/or perseverance. Examples of ascribed status include castes, race, and beauty among others. Meanwhile, achieved statuses are akin to one's educational credentials or occupation: these things require a person to exercise effort and often undergo years of training. The term master status has been used to describe the status most important for determining a person's position in a given context, like possessing a mental illness.