CAATs are likely to be the only effective way of testing programmed controls. Computer programs often perform functions without leaving visible evidence and the controls inbuilt in such systems cannot be tested manually. E.g. it is not possible to test the effective operation of passwords manually;
CAATs are quicker and more efficient enabling the auditor to test a large volume of transactions quickly and accurately;
Once acquired the use of CAATs is cost effective provided that they can be used in a large clients base;
Use of CAATs and especially audit software enable the auditor to test the accounting system directly rather than relying on printouts which could be manipulated by the client;
CAATs provide the auditor with additional options, there are certain audit procedures that can only be carried out through the use of CAATs.