The data contained in the files shown in Figure 9.9 provide evidence that may either corroborate or refute audit objectives. Most of the tests described in the following section involve using ACL to access and extract data from these files. For a detailed explanation of ACL commands, review the instruction manual that accompanies the ACL software and consult ACL’s online Help feature. As a preliminary step in using ACL, each file needs to be defined in terms of its physical location and its structure.