The correct answers are: CAATs are sometimes useful for testing 100% of transactions or items making up a particular balance; The use of CAATs on the client's accounting system requires the permission of and co-operation with the audit client.

Audit software can be used to perform calculations on and analyse the entire contents of, say, a receivables ledger. CAATs that involve the client's accounting system cannot be used unless the client both agrees and is prepared to assist the auditor.

Audit software is used primarily for substantive procedures, test data is used primarily for tests of controls. The use of CAATs normally requires special training.