33. The auditor should apply paragraph 98 of Auditing Standard No. 2 regarding an adequate period of time to determine the operating effectiveness of a control in the context of an engagement to report on whether a previously reported material weakness continues to exist. Paragraph 98 of Auditing Standard No. 2 states (in part):
The auditor must perform tests of controls over a period of time that is adequate to determine whether, as of the date specified in management's report, the controls necessary for achieving the objectives of the control criteria are operating effectively. The period of time over which the auditor performs tests of controls varies with the nature of the controls being tested and with the frequency with which specific controls operate and specific policies are applied.
For example, a transaction-based daily reconciliation generally would permit the auditor to obtain sufficient evidence as to its operating effectiveness in a shorter period of time than a pervasive, company-level control, such as any of those described in paragraphs 52 and 53 of Auditing Standard No. 2. Additionally, the auditor typically will be able to obtain sufficient evidence as to the operating effectiveness of controls over the company's period-end financial reporting process only by testing those controls in connection with a period-end.