Notice that the expense classifications--- controllable and fixed, and noncontrollable and variable---are not synonymous. In the short run, fixed expense usually are not subject to the same degree of control as are variable expense. Practically all variable expense, by their nature, are controllable in the short run. On the other hand, depreciation on an output basis, for example, is a variable expense that is noncontrollable in the short run. Conversely, certain salaries are controllable in the short run, although they are fixed expense.