A retail company uses a computer program that matches electronic vendor invoices with the applicable purchase orders and receiving information, which are also maintained electronically.
If an invoice does not match the other items within predefined ranges, a report is generated and sent to the accounts payable department for further investigation. All of the applicable documents are electronically marked, cross-referenced, and retained in open files. Both an integrated test facility and a systems control audit review file (SCARF) have been included in the system.
An auditor wants to determine the extent to which items are not matched at year end and to investigate the potential causes of the unmatched items. Which of the following audit procedures would be most effective in determining the items to investigate?