A hierarchical structure is a common way of organizing people and resources in many different organizations. There are several alternative terms which can be used to describe this type of structure. One such phrase is a "chain of command", which suggests a linear, top-down approach to management. Other synonyms for a hierarchical structure include "pyramid structure", "vertical structure", and "graded structure". These phrases all describe a system in which authority and power are concentrated at the top, with lower levels of management or employees relying on those above them for direction and guidance. Despite some criticisms of this approach, hierarchical structures remain popular in many fields and industries.