To fully document the system, you would continue to perform these decomposition tasks in still further DFDs. For example, you might decompose the procedure ‘‘compute payroll deductions’’ in bubble 3.2 of Figure 3-13 into several additional processes in lower-level DFDs—for example, separate DFDs for ‘‘compute medical deductions,’’ ‘‘compute savings plan deductions,’’ ‘‘compute tax deductions,’’ and so forth. In this way, a set of DFDs become linked together in a hierarchy