A type of communication that is beyond the control of management, is considered more reliable by employees than formal channels, and is mostly used to serve personal and social interests, is

Communication beyond management's control, trusted by employees more than formal channels and serving personal and social interests, is the grapevine.

It flows informally through friendship and social ties, spreading news faster than official routes.

Formal group communication is management-directed and structured, the very opposite of an uncontrolled informal flow.

Quality circles are organised problem-solving groups set up by management, not a spontaneous rumour network.

An external network links the organisation to outsiders, whereas the grapevine runs within among employees.

Its speed and perceived reliability make the grapevine a powerful informal channel in every organisation.