.11 

The independent auditor's objective is to obtain sufficient competent evidential matter to provide him or her with a reasonable basis for forming an opinion. The nature of most evidence derives, in part, from the concept of selective testing of the data being audited, which involves judgment regarding both the areas to be tested and the nature, timing, and extent of the tests to be performed. In addition, judgment is required in interpreting the results of audit testing and evaluating audit evidence. Even with good faith and integrity, mistakes and errors in judgment can be made. Furthermore, accounting presentations contain accounting estimates, the measurement of which is inherently uncertain and depends on the outcome of future events. The auditor exercises professional judgment in evaluating the reasonableness of accounting estimates based on information that could reasonably be expected to be available prior to the completion of field work. ^fn 5 As a result of these factors, in the great majority of cases, the auditor has to rely on evidence that is persuasive rather than convincing. ^fn 6 [Paragraph added, effective for audits of financial statements for periods ending on or after December 15, 1997, by Statement on Auditing Standards No. 82.]