…especially the meritocratic onces are not effective. Better are promotions by random. Sounds weird? Here is an excellent article based on a work about Peter-Principle.
Laurence Peter is a psychologist, who once said:”Every new member in a hierarchical organization climbs the hierarchy until he/she reaches his/her level of maximum incompetence.”.
A highly recommended reading from Principal Dialectica for all those who are interested in company structures.