The auditor can use other ACL features to seek answers to questions raised by the preceding analysis. For example, since this is a Sales Invoice file, it should normally contain only positive numbers. Negative numbers may have been inserted into the records in a number of ways. For example, they could be the result of a defective computer program, unintentional clerical errors, an effort to reverse the effects of erroneous sales transactions, or a fraudulent attempt to reduce a customer’s accounts receivable balance. Although the auditor cannot specifically identify from the stratification which records are causing the anomalies, the potential problem has been flagged. The auditor will probably want to pursue this matter further, but to do so will require more detailed information.