If there is an easy way to measure employee performance then the answer is no, random promotions are not possible. If employee X made 10 widgets in a year and e

If there is an easy way to measure employee performance then the answer is no, random promotions are not possible. If employee X made 10 widgets in a year and employee Y made 20 widgets then X might have grounds to sue the company if Y was promoted instead. However, it is rarely the case that things are so easy to measure. So-called "soft skills" such as communication and the ability (or willingness) to manage staff will often give organisations the additional leeway to promote a person who probably isn't actually very good at what they do. Sometimes (often?) this decision will be made because political alliances have been made. Other times it may be to fill a racial or sexual quota. These additional factors probably introduce a good deal of randomness into the mix when measured over time and averaged over all appointments.