I hold the view that in many cases comprehensive (or integral) checking of data with the aid of a computer is less costly and less time-consuming than selecting data for testing, and execution of the tests. I agree, computer audit programmers have to be compiled for this purpose, but then all the data the client is using are already in machine-readable form. In the Netherlands some public auditors, who are charged with the audits of banks, bring this into practice by simply duplicating the main part of the processing, using the client’s magnetic tapes and programs, as well as the client’s machine during hours specially assigned to them.