Companies distinguish operating departments (and operating divisions) from support
departments. An operating department, also called a production department, directly
adds value to a product or service. A support department, also called a service
department, provides the services that assist other internal departments (operating departments
and other support departments) in the company. Examples of support departments
are information systems and plant maintenance. Managers face two questions when allocating
the costs of a support department to operating departments or divisions: (1) Should
fixed costs of support departments be allocated to operating divisions? (2) If fixed costs
are allocated, should variable and fixed costs be allocated in the same way? With regard
to the first question, most companies believe that fixed costs of support departments
should be allocated because the support department needs to incur fixed costs to provide operating divisions with the services they require. Depending on the answer to the second
question, there are two approaches to allocating support-department costs: the single-rate
cost-allocation method and the dual-rate cost-allocation method.