Notice that the expense classification---controllable and fixed, and noncontrollable and variable---are not synonymous. In the short run, fixed expenses usually are not subject to the same degree of control as are variable expenses. Practically all variable expenses, 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 expenses.