Processing control is the control over the processing function of application system. The processing control should ensure that
Transactions are properly processed the computer
Transactions are not lost, added, duplicated or improperly changed
Processing errors are identified and corrected on a timely basis
The auditor should ensure that the audit trail in respect of processing of data the computer is adequate. It is very important for the auditor to understand each process performed on the input data. File controls and run to run controls are two major components of processing controls. For accuracy of the processing it is important that correct master files, transaction and programme files are used. In the case of applications consisting more than one computer run then it should be ensured that each run is accumulated and agreed with input totals to ensure the prompt detection of any lost, added, changed or damaged data.