FIGURE 11-3 Input test Auditor Predicted results Transactions to Test of Key Control Procedures Test Data Approach Key Control Based on an Procedures Understanding of Internal Control Application Programs Master files (Assume Batch System) Transaction files Contaminated Control Test esults Contaminated Master files Auditor Comparisons Differences between Actual nS, Loebbecke; Auditing, Predicted result @2000 Prentice Hall. IncArens, Loebbecke; Auditing, 8/E ©2000 Prentice Hall, Inc. Input Test Transactions to Test Key Control Procedures Auditor Predicted Results of Key Control Procedures Based on an Understanding of Internal Control Application Programs (Assume Batch System) Auditor Makes Comparisons Control Test Results Differences between Actual Outcome and Predicted Result Master Files Contaminated Master Files Transaction Files (Contaminated?) FIGURE 11 - 3 Test Data Approach