An internal auditor is asked to determine why the production line for a large manufacturing organization has been experiencing shutdowns due to unavailable parts The auditor learns that production data used for generating automatic purchases via electronic interchange is collected on personal computers connected by a local area network (LAN) Purchases are made from authorized vendors based on both the production plans for the next month and an authorized materials requirements plan (MRP) that identifies the parts needed per unit of production. The auditor suspects the shutdowns are occurring because purchasing requirements have not been updated for changes in production techniques. Which of the following audit procedures should be used to test the auditor's theory?