A supervisor achieves results through the efforts of other people on a short term basis, i.e. a supervisor runs a section of a business operation on a day-to-day basis, with responsibility for planning seldom exceeding a few weeks.
The supervisor is the link between staff and management, and performs the vital function of ensuring the efficient leadership of all productive effort therefore the supervisor is ultimately responsible for the productivity of the line staff.
A manager also achieves results through other people but has the added responsibility for medium and long term planning. A typical middle manager would occupy his/her time equally between ‘supervising’ and ‘managing’, while a senior manager would be occupied largely in the planning and tactical functions and would be operating more as a pure manager.
Having job descriptions with clear responsibilities is key to ensuring that these roles don’t overlap.