Time-scale promotion refers to a promotion that is based on an employee's length of service in a company. There are several synonyms for this type of promotion, including seniority promotion, length-of-service promotion, or simply tenure promotion. These promotions are often granted to employees who have stayed with a company for a certain amount of time, regardless of their job performance or skills. While they may be a way to reward loyalty, time-scale promotions can also lead to resentment from employees who feel that promotions should be based on merit and job performance, rather than just time served.