Ashton Tate, an in-charge auditor, has completed the year end physical inventory observation at a large wholesaler of automotive parts. Tate reviewed management's inventory-taking instructions before the start of the physical inventory, made and recorded test counts, observed the controls over the inventory-taking process, and noted no significant exceptions. Tate's subsequent comparisons of the quantities shown on the count sheets with quantities listed on the perpetual inventory records disclosed numerous discrepancies.

Required: 

Other than theft, what are the likely causes of the discrepancies?