The most important control to assess in an audit of an organization’s accounts payable processes is segregation of duties between issuing purchase orders and making payments. Segregation of duties is a principle that requires different individuals or departments to perform different tasks or functions within a process, in order to prevent fraud, errors, or conflicts of interest. In the accounts payable process, segregation of duties between issuing purchase orders and making payments ensures that no one person can initiate and complete a transaction without proper authorization and verification. This reduces the risk of duplicate payments, overpayments, unauthorized payments, or payments to fictitious vendors.